Yes, the genocide during the Bosnian War was very much a planned endeavor on the behalf of Serb military and civilian forces, though at times it did happen organically. It's important to understand, however, that the genocide in this context was not necessarily the organized camp killings one thinks of in terms of the Holocaust (though prison camps certainly existed). Instead, much of the genocide was carried out through ethnic cleansing, a general pattern of murder, rape, and pillage specifically targeting non-Serbs in an effort to drive them out of their homes. Srebrenica stands out among this because it was a full-on massacre, as opposed to more roving death squad style killings. Most of the killing was carried out by paramilitary units following behind Bosnian Serb military forces (BSA), however, the BSA itself participated frequently and vigorously. According to the Balkans Task Force (BTF), the joint intelligence unit set up in the United States to monitor the situation during the Balkans Wars, most paramilitary units, such as Arkan's Tigers, "appear to operate in close coordination with the Army, if not under its command." Similarly, the BTF concluded that, "the systematic, widespread nature of Serb actions strongly suggests that Pale [capitol of the Republika Srpska, the Bosnia Serb independent state]... have exercised a carefully veiled role in the purposeful destruction and dispersal of Bosnia's non-Serb population." Even Radovan Karadzic, President of the Republika Srpska, denied his role in ethnic cleansing organization while simultaneously organizing some of the worst detention camps of the war. Similarly, the CIA concluded independently in 1993 that rape was being used as an organized method of ethnic cleansing among Bosnian Serb forces, both military and paramilitary, providing a map of organized detainment facilities in which rapes were occurring on a regular basis. Similarly, a National Intelligence Estimate in 1993 concluded that the Serbs would commit "determined ethnic cleansing", implying a coherent plan for carrying out such actions. Given these real time assessments, alongside the evidence and testimonies present to the ICTY (which I would love to provide, but alas, I did not study that area very heavily and would not feel comfortable commenting on it), it is impossible to deny that the ethnic cleansing occurring in Bosnia was not an organized, well-orchestrated endeavor.

As for your second question, the answer is no, the Serbs were not the only perpetrators of human rights violations during the Balkans Wars. All faction, including Bosnian Muslims and the Croats, perpetrated at least some ethnic cleansing. In September 1995, the BTF found evidence of Croatian military forces carrying out small-scale ethnic cleansing during the military offensive known as Operation Storm. Ante Gotovina, a leading Croatian military commander during the Croatian War for Independence, was actually indicted for ethnic cleansing by the ICTY but the charges were later overturned (this happened recently, so can't really get into it per subreddit rules). However, it should be noted that while all sides did enact some sort of crimes against humanity, no other faction matched the size, scale, and organization of specifically Bosnian Serb efforts. In 1994, when the CIA released its definitive study of ethnic cleansing in the conflict up to that point, they clarified that, "Although all factions have been victims, Bosnian Serb forces appear to have been responsible for at least 90 percent of ethnic cleansing that we have identified." In other words, the Bosnian Serbs were perpetrating the lion's share of atrocities during the conflict by a significant margin. For example, there was no Croatian or Bosnian Muslim equivalent to Srebrenica, and that's ignoring the numerous other actions of Bosnian Serb (and regular Serb) military forces in the context of military actions that were unnecessarily violent or destructive towards civilians (such as the perpetual bombardment of Sarajevo on crowded market days).

Sources

National Intelligence Estimate, “Combatant Forces in the Former Yugoslavia,” June 1, 1993, Bosnia, Intelligence, and the Clinton Presidency, CIA FOIA Electronic Reading Room, 1993-06-01, available at http://www.foia.cia.gov/document/5235e80d993294098d517563

CIA Memorandum, “Ethnic Cleansing in Bosnia-Herzegovina,” April 29, 1994, Bosnia, Intelligence, and the Clinton Presidency, CIA FOIA Electronic Reading Room, 1994-04-29, available at http://www.foia.cia.gov/document/5235e80c993294098d5174ab

BTF Assessment, “Bosnia Serb Ethnic Cleansing,” December 1, 1994, CIA Memorandum, “Ethnic Cleansing in Bosnia-Herzegovina,” Bosnia, Intelligence, and the Clinton Presidency, CIA FOIA Electronic Reading Room, 1994-12-01a, available at http://www.foia.cia.gov/document/5235e80d993294098d5174e9

CIA Memorandum, “Rape As An Instrument of Ethnic Cleansing,” April 2, 1993, Bosnia, Intelligence, and the Clinton Presidency, CIA FOIA Electronic Reading Room, 1993-04-02, available at http://www.foia.cia.gov/document/5235e80d993294098d517582

BTF Assessment, “Propsects for Ethnic Cleansing in Sector East,” September 11, 1995, Bosnia, Intelligence, and the Clinton Presidency, CIA FOIA Electronic Reading Room, 1995-09-11b, available at http://www.foia.cia.gov/document/523c39e5993294098d51763b

Samantha Power, A Problem from Hell: America and the Age of Genocide

Cees Wiebes, Intelligence and the War in Bosnia, 1992-1995

Edit: Thanks for the gold!