Here's what I'm thinking based on what I've seen...
You get 1 "free" OTG per combo, where you can scoop up a character in a hard knockdown state on the ground with any move that will hit them.
You get 1 spike bounce after using your spike move after an air combo. This bounce is smaller than normal, but allows you to combo using most regular moves.
The 1 regular ground bounce and 1 regular wall bounce rules per combo still apply (except for Power Stone Surge).
Some moves still have the capacity to straight up OTG. Moves like Strider's Satellite, Dante's startup to beehive, ect. These moves can continue to actually pick people up off of the ground similar to UMvC3 when they are in a hard knockdown state there are no more "free" OTGs.
I THINK that's how it goes, but not positive. It's weird though, because even with all the new additions to the system, it seems like if it is this way, the game would still eventually lean more towards characters with the capacity to straight up OTG, which it seems like they were trying to avoid by adding all these new mechanics to the system to help characters that can't.
Yes.
Basically the universal OTG is not the same as an OTG move. OTG moves can continually pick people up until the hit stun deterioration runs out and they flip out.