Fix the leak. You can't troubleshoot a car with known problems. Especailly problems related to the symptoms. If you fix the leak and you still have issues, then look further.
But FWIW, you said you did a MAF before the parts were installed? If you installed rockers and headers, you majorly changed the performance of the engine. You need to do a VE tune and MAF tune after you install the parts. While the vacuum leak will affect the trims like you said, the lack of a good tune for your engine and mods will also make a huge difference.
