Killey, I think he meant to add in qcb+D, qcb+D (whiff) into the combo. You're in too much recovery after the EX fireball to run-up and qcb+D, qcb+D (whiff) works just in this scenario.
Cross up set-up #1: 1 x d.B into regular hop
I've been trying to play with K' cross up setups. They're really hard to do for me! I've found that after 1 d.B, you can cross up on someone. Here's the bad part. You have to do the jump C at a very strict timing to cross up. However, there's an upside to it.
You can make fake-cross ups with K' if you get the timing. You could make someone block the wrong way by doing it early and it's still deep enough of a hop to combo if you get the cross up of your don't. It's really interesting what you can get off of it.
The best way I can think of setting up is this: d.B x2 (Blocked), dash up, d.B (blocked), hop over for cross up
Cross up set-up #2: d.D (sweep) into vertical super jump
If you get a knockdown on someone with a sweep from point blank and they don't tech, you can super jump over them on their wake up and cross-up with hop C. Same thing here, you can do a regular jump and make it a little ambiguous, but unless you walk up a few steps prior, it won't cross up. Hyper hop won't either. You can use blackout to cross up while they're knocked down. The farther you are when the sweep hits, the closer you'll be to them when you get behind them (except in the corner of course). You can use this to stay in your opponent's face instead of going for a cross-up cross up. At the max range of a sweep, you're close enough to do d.B. At point blank, you're safe from most moves. Be weary, if they fall break the sweep, you won't be able to cross up.
Cross up set-up #3: d.b x2, A Ein Trigger, run-up into super jump
You can set someone up for a cross up after this special. You can actually hyper hop using this set-up if they block it. It's self-explanatory. On a knockdown, K' can go for another jump C cross-up. You can time it early to make it not cross-up, but it gives you more control and options after an Ein Trigger. It also gives you more reason not to cancel into Second Shoot or Second Shell when you score a knockdown. If they fall break the knockdown, you won't be able to cross up as easily, but you can still do it.
That's all I got. With his normals really nerfed, his set-ups are kind of weird. Something with a diagonal hitbox is his blowback. Might not hurt to do some research and see if using that to cross-up would work.