Another option that is out there is a battle belt for load bearing gear, Is very cheap to get and can be modified and added to as time goes on. This has been my go to system for the last 2 years and has been going strong since. Light, Breathes well and can be modified quite a lot (at least I like to think so)
Pistols are not really needed, I'll be honest I the last 2 times I've gone to a local CQB field my pistol has sat in my holster and seen no use.
As others have said I WOULD HIGHLY recommend trying out a few guns at the local field or shop and find what style you like. You could find that the M4 Doesn't fit you well but you could love the fit of the M16, AK, MP5, M14, AUG etc.
Best of luck!