Ok, couple things.
First, no weird races besides what I've already laid out. Let's keep that simple. Very simple homebrew class stuff can be accepted, besides the ones I already listed. I want to keep this as simple as is possible.
Firearms requires proficiency, or a feat, and if you don't have it, not only do you have disadvantage on attack rolls, but you have a decent chance every time you use it of it getting jammed. Cause reasons. I'll work out what the feat does, but it should be good. Probably similar to Crossbow Expert. In fact, I may just say Crossbow Expert applies to handguns the same way it does to hand crossbows.
Bows and crossbows are still things.
You can make a gunslinger, but no new gunslinger class. Work with what you have.
If anyone is playing a warlock, or thinking of playing a warlock, PM me.
All those other rules apply. Magic users are strictly enforced. They have to wear special clothing. They have to be on official business. Unless you're a Pariah, in which case you'll be hiding who you really are.