I covered earlier the source of Mecha Wiggler's power in this thread. I'll post some pictures with captions to make it quick to catch up

The source is the city's energy!

Which in turn is powered by many Power Moons...

... their energy being good enough to help build a city.
However, it seems to be concluded that the Moons didn't create the city themselves (albeit there are a few implication, but... let's not try to go too far with all this), but rather their energy aided the construction... but still, they undoubtably power the city (see picture 2), so the energy Mecha Wiggler is absorbing is actually from Power Moons essentially.
But... we still don't know if Mecha Wiggler /would/ scale to Mario, if its questionable as to if they can even reach city level. Sure, the Multi-Moon might have created realms in paintings, but... none of the arenas were that big, apart from maybe Lanceur's rematch (the octopus), and we don't even know if they /did/ make those realms.
And, Shirm isn't necessarily stornger than Mecha Wiggler... Minor Mario enemies generally don't scale because they hurt someone, and it was only shooting the weak spots when vulnerable that hurt Mecha Wiggler... So, no, I don't think they'd scale.
We don't quite know if
turning day to night was a feat in the end, but I did cover it already in the Part 1 blog on Odyssey's powers and abilities... but also covered how moving a star would not be how day and night works.
And yeah, definately got to add weather maniupulation to the blog, since we've now got two cases. Ice manipulation too, of course.