If God appeared to me I'd have several reactions. First, I'd have to say 'Good for you, you took your time but you've finally made it. Could you let your followers know just which sect is the right one. It would really make things a lot simpler.". If, as I walk away, God asks where I'm going then I'm simply going to say, "Just going back to getting on with my life. Let me know if there's anything you need and I'll see if I can help you out. Oh, before I go could I ask you to keep an eye on those followers of yours, now you've put in an appearance they're likely to kick off a few holy wars to establish their claim to be your favourites.".
More evidence showing up for Jesus. Without a bit more context all I can really say is that my reaction would be, "That's nice for you!". I really can't say more than that. Having evidence of anything does not qualify it for any inclusion in my life. He's had no effect on my life so far, so it's a bit like saying "I can prove the president of Lithuania exists". That may be, but it makes no difference to me.
... more proof that a God would have to create the universe?
More, I wasn't aware that there was any proof already!
I'm pretty content that the creation of the universe is covered with brane cosmology, wave/particle duality and information theory.
Would I become a Christian? No, I can accept a god proving itself to exist but I cannot accept that there would be a requirement for me to worship it. The establishment of religion carries the implied notion of worship which I see as purely egotistical and damaging both to the worshipper and the object of worship. I always equate worship with obsession and a weak will.
Would I treat Christians the same? Yes, as long as they let me get on with my life without interference them I'm happy for anybody to believe what they want. I treat religious folk as having a religion as a framework to hang their view of the world on. That's fine and I respect that but they have no authority over the framework which I hang my views off of.
As for Hell, I don't care about that because I know that even if it does exist (I know it doesn't) I know I won't be there forever.
Repent? Repent what? I've never sinned and never will so I don't see that repenting will ever be necessary.
Can I ask you, OP, a question? What would you do if God appeared, confirmed everything in the Bible is pretty much true and then declared that He couldn't care less about what happens on Earth and that we're free to get on with whatever we want do? There'll be no Heaven or Hell, the life you're living is it, no more, no less. Would you still be a Christian?