Would an IAC lever action 12g with 28 inch barrel make a good all round hunting gun?

I think It'll do just fine for the game you have mentioned, provided your within the range depicted by your loads. As long as your using quality shells and appropriate shot for said game. Be careful with your choke when firing slugs though. I've heard you can cause severe damage to your barrel although you're probably aware of this. I must be honest, I'm not terribly familiar with lever action shot guns, but It seems like a very appropriate action for your situation. Good luck and happy hunting.