I just can't ship them at all. "I am your Soulmate" only made me feel uncomfortable.
I mean, kinda same? Even Alice there didn't say more than "we'll look for Iruma together". That's, at most, a very definitive polycule thing, than any particular romantic affection he feels for Clara.
And at the least, it is just declaring that they would remain (all three of them) besides one another, and look for ways to bring whoever might leave back together with the rest.
He didn't deny that Iruma is the thing that keeps them together, and a much better question is whether they would even be together if Iruma was never around (before or after). The answer is a very clear no, but making her not wonder over hypotheticals and value the weird yet strong relationship between all three of them (and maybe helping her realize the bonds she has with some of the girls in the Misfit class as also valuable relationships) would be a stronger resolution over this one.
To me, it glosses over the core of Clara's issue, not having fit anywhere before and fearing to return to that, to focus on the specifics of losing her most precious relationship besides her family - and feels equally as weird as the resolution of the long-eared tribe's issues. A resolution that isn't actually addressing the core of the issue, yet with the presentation showing them as definitive.
At least the core of the writing remains enjoyable.