Astral Projection
AP allows for Jinpachi to navigate quickly across of the stage with near instant start up, but noticable lag towards the end of the animation. Luckily this "lag" is due to allowing for AP options (e.g. AP 1, 2, or 1+2) to be input until the animation finishes. What this allows you to do is react upon what the opponent is doing and punish accordingly. For instance, the opponent does a standing +frame option and follows up with a "guaranteed 50/50". Instead of facing the 50/50, you can AP backwards to completely escape. Now if the opponent does an advancing attack that extends them just a little too far, you can punish with a AP 2 and KND them into your own 50/50.
An important property of AP that survived from DR to TTT2 is that AP can crossover the opponent while they are KND or recovering from grounded (i.e. rolls, wakeup kicks, flinches, etc. Example can be found here). While impractical in offensive capability, unless something new is discovered, this can be a valid strat for escaping corner pressure with Jinpachi's plethora of NC and NCc KND attacks.
By early in day 2 I had a much better grasp of AP as an offensive tool, best example I found is during this match here. Starting about ~1:20:31 I rot the point character's health down with a couple of strings and then score a KND. I throw out AP 2, with its quick recovery, as bait for the opponent to attack from grounded. They opt for wakeup 3 and I punish accordingly with WS+4,4 resetting the situation to what it was at the beginning of the clip. I push them a little further toward the wall and then use AP 1 to hopefully catch wakeup kick or duck, either case should W! them and put the momentum highly in my favor. Luckily (and possibly surprisingly) Asuka tries to punish with a b+4, but I recover in time to block it.
In such a way AP is very similar to Feng's KNP stance, but without the fun of being just out of your opponent's range. On one hand it's much hard to punish with attacks out of stance against whiffs, but on the other hand would be immune to a ton of long range advancing mid attacks that would normally catch sway type stances. As such b+3+4 is better used as an escape mechanism, while f+3+4 would be more for wakeup pressure and opponent tag anticipation.
Anticipation and FLY
While the input frames for AP allows for delayed/reactionary attacks, FLY requires considerable anticipation and/or reactions to trip up your opponent. The problem with fly, in its current form, is that the appropriate attack must be input as soon as u/f+3+4 is hit. Therefore once you hit the skies, you should have some sort of plan dependent on level positioning and/or opponent health. For instance if the opponent's back is to the wall, you have a 50/50 with FLY 3,4 for wall splat or FLY 4 for guaranteed follow up or 50/50 W! options.
Here's a pretty good example of reading the opponent's options and attacking accordingly. Once again I score a KND with d/b+3,1 (workhorse anyone?) and see that the opponent ground rolls into the foreground and stays grounded, presumably to see if I'll whiff and therefore can be punished by FDFT D+3 or some derivative. I recognize that the opponent, from this position, can not roll on the ground again and therefore must either quick stand guard or roll away. Since I dashed into the range where FLY 4 will also catch back roll, the opponent was dead in the water and (unknowingly) forced to take the grounded hit.
Charge Stance
There's not much to say about his charge "stance". It's a much needed change as now Jinpachi has a proper supercharger/ki charge with 1+2+3+4 and since "charge stance" now has stance properties, namely no CH in a stance unless you are attacking, he can't be CH launched while charging like he could in DR. In theory, charge sounds great: no CH anymore while you are "charging", charge 2 has standard Mishima EWGF properties (including +frames on block), and charge 1 might be way less than launch punishable on block.
In actuality, I can't really find where "charge" fits as a whole. Since Jinpachi ducks so low, I have to assume he high crushes and his charge 1 (TGF) may retain some ridiculous mid crushing properties, but overall charge is just too damn slow. From this video you can see that charge 2 has poor tracking while charge 1 looks to be Jinpachi's answer to tracking SS. Unfortunately charge 1 is similar to standard TGF in the fact that it doesn't launch and instead can KND/W!, but possibly might have wonky requirements for combo as the recovery on hit is most likely still poor (compared to DR and/or TGF in general).
"So, when to charge?" I'm still not sure, but there's only two cases where I see it being usable.
A) Against jab/high attacking characters, assuming charge properly high crushes throughout it's startup and attack
B) When properly spaced to cause the opponent to whiff during wakeup, but even then this charge 2 is a high, so you'd need to react properly to wakeup 3