That should be fine. That's how I incubate my corn eggs - nothing fancy. Top of a closet works great! I always check the sex of snakes I get on my own just to be sure; I'd recommend doing that from now on. We all make mistakes, and it's possible for whomever you got yours from to make a mistake as well.
I've never heard of males trying to mate another for dominance; at least not with snakes...
Good luck with them, hopefully the clutch will make it.