What is Cave Diver Training? 

Exploration level diving is outside the scope of this conversation and isn't a realistic goal for most divers - especially exploration for something like "god's chalice of scuba" aka Hill 400. I suggest you stick to hobbyist depths and distances.

That depends. Ideally the seesaw of experience weighs heavy on one side. For example - 500 hours of great lakes deco CCR diving - let's do cave CCR to start with no OC cave. If you have hundreds of cave dives over many years and then start CCR diving - a cave CCR crossover sounds swell. Where people get into trouble is a low amount of tech diving experience and/or low CCR hours trying to get into cave ASAP. The seesaw of experience needs to weigh heavy in some way. If the student doesn't have much OC tech experience or CCR experience and is really interested in ccr cave (this is what I see most commonly) then I'd suggest OC cave, go on a few dozen cave dives and then think about cave CCR crossover assuming they have the requisite CCR hours. When it comes to CCR diving - cave diving in particular - diving experience is of greater value than certifications. That's a... pseudo short answer. Feel free to ping me direct for more long winded opinions!

@@BarefootBentley for cave diving I am all about being slow