How would other deities react to a god living openly among mortals?Depends entirely what that god did. And how can you be sure that situation isn't already in play? Gods are pretty good at keeping secrets from us.
Why of course! One walks among us this very day! The Living God Razmir is all the evidence you need for your question! (Glory unto him!)
For James: Why does your puny bug goddess with a starlit twinkle in her eye keep attacking our priests! It's rude I say!