Just a note. Just because Ulq has the extra form doesn't mean the others can't reach it easily - He just says they haven't. It also doesn't mean that he's number 1 worthy. Number 5 could have had 3 forms and still gotten his ass kicked by Ulq level 2.
He could be stronger than Stark, and as far as series timing goes, it'd probably be a bit better if he was, but that's not Shonen like, and they could get away with another 250 prints.
Anyway. Breakdown.
Don't be surprised if they go back to the surface after this chapter.
Ichigo goes full Hollow. He can win that way. Especially with the Hueco Mundo boost.
Orihime reverts him with her TIME MAGIC.
Ichigo grows afraid of the mask -again-.
With all the baddies in Hueco Mundo dead, they can finally be rescued by their friends. If it's good writing, they'll skip to Mayuri before they show up to make it seem like less than perfect timing. If it's bad writing, it'll be like ten seconds later, 'Sorry we sucked too much to help.'
The surface Captains lose. Yama-Ji dies. I'm predicting it's not even close.
Number 2 being the only Espada that dies. I mean, he's old, and he's a bossy villain. Shonen death waiting to happen.
The Hueco Mundo captains and friends appear to stop the 5 enemies that are left.
Give or take details.
Now the story can go two ways from there. Aizen can claim and show he's already won and go become King or he can retreat for now, rebuild the Espada and become King later.
He has to be King when Ichigo kills him, though. And he's obviously very far from being ready for that.