That post-Gorath setting packs some glorious worldbuilding, albeit 'building' ain't the best choice of words. Some dubious observations: (1) Battra needs Zilla-season backup yesterday; (2) ditto for Dagarah, as its sea stars were never bioengineered for pollution with a Hedorah's moxie; (3) warped climax proposal for the (Mecha)G-War: Kiryu Squad, absorbing a near-meltdown Godzilla's excess juice, wind up 'rejecting' their cybernetic bits for a fresh lease on life. Hail to the new Royal Clan.
I can image there’s a squad of ’Lizard Slayer’ mechs at work in the US protecting the inland communities from the more aggressive and intrusive Zillas. And possibly from DRAGMAs as well. Considering that three of these mechs were unable to defeat one Zilla in Godzilla: The Series, I can’t imagine their success rate being very high. Still, the engineers diligently reassemble the robots out of both new and partially destroyed parts and send them back out, driven by pilots trying their best.
Dagahra is on its own, though. There’s no Mothra Leo to magic away all the pollution at that point. Wouldn’t it be a hoot if Dagahra became Rainbow Dagahra or Armor Dagahra somehow?
As for the Mechagodzillas, while all three of them reviving is an interesting prospect (especially if you take into account they may not all be on the same side), I was thinking along the lines of that old “Godzilla vs. Berserk” concept. Basically one Mechagodzilla develops a virus or partially revives and becomes a hulking mass of assimilated machinery and regrown organic matter.