You don't think there will be any hiccups with the tubing being lower than the drinking point? I don't have any experience with this system but it is something I've been reading about a little bit in relation to quail keeping, if I decided to go with cages at any point.
Another fix I might have done would have been putting some hardware cloth at the bottom outside of the bun cages so they couldn't stick their paws and faces through the cages. So many different fixes! :)
I don't think so. The five gallon bucket reservoir is high enough.