We're coming up on the final battle, every named good guy char needs someone to fight to create tension and drama during the battle. Tieria has relatively few connections with bad guys (I'm assuming Regene will be dead by 5 min into next ep) and so revenge for his bromance with Lockon I is probably his best hope of facing off against a named char and having a good reason to angst. Setsuna and Lockon II may also have bones to pick with Ali butthey both have bones with other named chars as well. Lockon II also bones with Revive and maybe even Hilling since he's rather anti-Innovater. Setsuna also has bones with Ribbons 'Dark Amuro' Almark (and hopefully will face his Dark Nu Gundam instead of an FBMA) as well as Louise (via Saji). Al/Hal doesn't really have bones with anyone named so he'll probably get shoehorned into fighting Hilling and a clone army while Soma deals with Andrei and more clones.

I just hope Veda's asteroid turns out to have a death ray. It wouldn't be a Gundam final battle if there wasn't a threat of a superweapon looming over the battlefield hastening the cast to defeat the enemy before all hell breaks loose.