couple of tips. First is a shameless plug but none the less it will help you out
www.keepingandbreedingbristlenose.com
you will find all the information you will ever need i there, everyone who has bought it agrees.
To answer your specific questions, Bristlenose fry need vege matter just like their parents. BBS will most likely kill them. They need the same diet as their parents. I recommend cucumber (not blanched) or de-shelled peas (blanched).
The Khulis might have a go at getting into the cave to have a go at the eggs and wrigglers but dad should be on top of that. It will depend on the type of tetra we are talking about. Neons will be fine, Piranha will be a bit of an issue hehe