Besides Pearl Harbor, why weren’t there any invasions onto American soil durring WWII?
Because the Japanese absolutely lacked the logistical capability to do so. I've written about this before:
Technically, the Japanese did invade part of America -- two small islands in the Aleutians, Attu and Kiska -- as part of the Midway operation, but the islands were essentially uninhabited, and were taken back easily when the U.S. got around to it.