TRACON Controller reported aircraft repeatedly penetrated Class B airspace; which caused a departing aircraft to descend below the minimum vectoring altitude to avoid conflict.

Narrative

Aircraft X; flight of 4; departed ZZZ to hold southeast of Location 1. Asked to hold at 030. Sector told ZZZ to put the aircraft on Departure East frequency. I told the Departure East Controller to hand off the aircraft to Sector Controller and to instruct Aircraft X to maintain 035 to stay above ZZZ airspace and to top props off of ZZZ. Departure East Controller said he would work the aircraft and wanted him to stay VFR at 030 so that it would be easier to top the Aircraft Y's if they are low. Aircraft X flight then flew repeatedly into ZZZ airspace. Aircraft Z departed ZZZ IFR talking to Sector position was instructed to climb to 4 and turn to 110 heading to avoid the Aircraft Y that had penetrated ZZZ airspace. Conflict alert went off; traffic was given; and Aircraft Z descended into the TV antennas south of ZZZ at 2100 ft. MVA is 3000 ft. and towers are 2059 ft. I informed Departure East to give Aircraft X brasher warning for a pilot deviation.The entire operation was unsafe. I was in charge and was ignored in regards to altitude to maintain and controller who should work the Aircraft X flight. I would advise the controllers to to keep traffic in a safe altitude away from departing traffic and talk to the correct controller.