Having read through/listened to more than 30 Japanese American oral histories produced during the 1960s to 1980s, I believe I can answer this question with some reasonable depth.
My sense in researching the Japanese and Japanese American perspective from around 1900 to 1950 in southern California, was that the attitude of their captors and discriminators changed from one of suspicion and hostility at the beginning of the war, to one of soft acceptance. And, when you say "federal workers" I will assume that you mean everyone from the executive cabinet level, down to rank and file soldiers and administrators.
Beginning with Pearl Harbor, Japanese and Japanese Americans were immediately under great suspicion and many men of fighting age were immediately detained by the FBI, often for reasons as oblique as being a teacher at a Japanese language school. Amy Uno Ishii's father, who had arrived in Seattle in 1906 and was living in Los Angeles when Pearl Harbor was attacked, was immediately taken away. Ishii said that the FBI was "tearing out the floorboards, taking bricks out of the fireplace, and looking through the attic" when she arrived home (5). For reference, most Japanese and Japanese Americans in southern California were relocated to incarceration camps like Poston in Parker, AZ or temporary detention centers at the Pomona race tracks from roughly February 1942 to May 1942. Ishii's brother who was serving in the National Guard was given a dishonorable discharge for "being an undesirable Japanese who was not to be trusted." Amy and her siblings were of course born in the U.S. During the war, federal authorities repeatedly tried to put Ishii's father on a boat back to Japan, but he vehemently refused, each time being returned to a new incarceration camp, before eventually being reunited with his family. Kiyoshi Shigekawa who was born in Los Angeles in 1912, along with his wife, were repeatedly incriminated for tenuous connections to the Japanese navy while incarcerated at Poston. While attending USC, a Japanese naval officer visited USC, where Mrs. Shigekawa attended; her professor introduced the two to each other, who stood for a photograph. Throughout their oral history, the pair agreed that federal investigators attempted to pin a variety of odd connections to the Japanese state on the two, which they resisted. It is worth noting that Shigekawa was one person who protested and took to court the legality of their detention, and also wrote letters to the president about the unfairness of the draft compared to their incarceration. Mitsuo Nitta, who was born in Santa Ana, CA, noted that immediately after Pearl Harbor, "the FBI had knocked on the doors of people whom we knew....people that I think were more the Buddhist-oriented families." (13)
Although many of the Japanese from southern California described being targeted by federal authorities immediately after Pearl Harbor, plenty of Japanese Americans were spared for reasons we can only speculate. Henry Kiyomi Akiyama, who was born in Nagano prefecture and came to the U.S. in 1907, was not immediately detained after Pearl Harbor, but treated as a non-threat and moved to Poston incarceration camp six months after Pearl Harbor was attacked. Akiyama, who ran a goldfish farm in Huntington Beach, CA, speculated that he was spared from being put in an enemy alien camp because he employed white folks at his business. Clarence Iwao Nishizu, who was born in Los Angeles in 1910 and grew up in Orange County, CA, was an avid participant in Japanese martial arts, including sumo and judo. These were traits that seemed to typically draw suspicion from American federal authorities because of the perception that Japanese martial arts included some allegiance to the Japanese state or emperor. Nishizu even participated in a Japanese American judo tour to Japan and its empire, which included Manchuria, and Korea in 1931. He also met a handful of high ranking Japanese officials including Admiral Heihachiro Togo, Hatoyama Ichiro, Isamu Takeshita, Fujinoma Shohei, and Tokonami Takejiro. Yet, Nishizu escaped immediate detention and was even allowed to try to find a place for his family inland of the west coast exclusion zone. He did not succeed and was eventually relocated to Heart Mountain incarceration center.
The discrimination and hostility continued unevenly, and seemed to break away in some measure throughout the war.
Mitsuo Nitta, mentioned above, a Santa Ana, CA native and farmer, enlisted in the military in February 1942. After completing basic training in APril, he was selected to attend officer school. However, his platoon leader told him "practically in tears" that "the colonel had stated there would be no 'J**s' going to OCS out of his regiment." In 1944, Nitta was eventually allowed to attend officer school and was commissioned in January 1945 from Fort Benning.
Many Japanese and Japanese Americans who were incarcerated were allowed leave from their camp throughout the war, indicating a growing amount of leniency and dwindling hostility at least from the camps administration. Mary Nitta, who married Hitoshi Nitta (related to Mitsuo Nitta mentioned above), had been at the end of her nurse training right when Pearl Harbor was attacked. Sometime in 1942 or 1943, she was allowed to travel to USC to take state board exams for nursing, where she was escorted by a white woman. Nitta was also allowed out of Poston incarceration camp once, although I'm not clear what year that was. During that outing, she went to a burger shop where many camp staff and military police ate at (presumably this is at Parker, AZ, the nearby town), but was denied service because she was Japanese. She told one of the camp directors, who in turn forbade all personnel from going there from then on, and in Nitta's telling, that bankrupted the burger place.
Many of the incarcerees were also allowed to leave to make money doing farm work. The labor was typically far away, and often difficult. Many of the incarcerees mentioned doing "sugar beet topping," which I can only imagine was very difficult and strenuous work. They would typically spend a few months at a time laboring at a farm before returning to whichever camp they were incarcerated at. Roy Kobayashi who grew up in Orange County, even worked on Sect. of Interior Harold Ickes' farm on the east coast. Many also returned to their west coast homes to check on their property. Kiyoshi Shigekawa returned to Anaheim, CA for three days in 1943 or 1944, accompanied by a military escort. He says that he had a "hell of a time" visiting friends, suggesting he made a good time of it. Charles Ishii and Henry Kanegae also briefly returned to Orange County to check on their land, before returning to incarceration.
Without discussing legal challenges to incarceration and to conscription, we might be able to say that federal relocation authorities even began to actively support Japanese Americans as they returned to their communities. When Hitoshi and Mary Nitta returned to Orange County, CA, a group of farmers tried to intimidate her and her husband, telling them to return to incarceration. After this happened multiple times, they called the sheriff who did not take their complaints seriously. Then, they called the War Relocation Office, who called the main office in San Francisco, who then contacted the attorney general of California, who in turn called that local sheriff. He became more responsive afterwards.
In conclusion, based on my reading of Japanese American incarcerees oral histories, I would say that a "typical attitude" of a federal worker would be hard to pin down. Whether the FBI rounded up a household's patriarch seemed to differ widely, sometimes based on how "Japanese" the family appeared, but with some very notable exceptions. Nonetheless, hostility and suspicion was palpable in different government offices, as indicated by dishonorable discharges or the withholding of officer promotion. Also of note, I did not see mention of deliberate mistreatment or active hostility from camp staff/soldiers who kept incarcerees in their camps. Over time, these positions appeared to soften, with Japanese incarcerees allowed flexibility to travel to their former homes--if they still had anything in those places--and allowances to leave camp and live in cities far east of the western exclusion zone. Over time, this may have morphed into more active support of Japanese Americans from federal agencies, but it is not clear that it was systematic in any way.
Oral Histories
If you would like to learn more about the racialization of Japanese during World War 2, I would suggest Race for Empire by Fujitani, and War Without Mercy by Dower.
Edit: A couple points I thought of in the last few minutes. Another book that is really interesting in thinking about Japanese Americans is Azuma's In Search of Our Frontier. Also, searching the portal where I linked the oral histories for federal workers could help answering this question!