Okay, so we got our ultimate constellations. They're really, really good as expected. Was kind of hoping for subtypes, but whatever, I'll take it.
The lead/sub split is slightly unfortunate since I use Alrescha as both, but honestly the lead for doesn't seem that great. 30% damage reduction to 1.3x HP and defense seems equitable until you realize that the stat boosts only apply to machines and machine team still isn't a thing. I mean, the damage boost is very good for sure, but I'm not sure it's worth the likely significant bulk loss.
The sub forms are crazytown though. Skillboosts is, obviously, exactly what the constellations needed to be basically perfect. God Killer is a nice bonus, but certainly not needed. As much as I hate to say it, I think ultimate Alrescha fully outdates Reine on my Gabriel team. Reine is still preferable on NepDra though, so that's good.
Significant Chinese buff is significant, although the way PDX refers to the Chinese as "Haku and friends" makes me cringe.
UmiYama buff still seems weak to me. I don't know. Compared to Ra or Sakuya they don't seem like a compelling rainbow lead.