The Creation Trio vs The Ones of Mortis

Welp, there's always shadow mewtwo's planet rape. 🙂

How does Abeloth fare against Lugia and Ho-oh? And Celebi?

Probably loses to Lugia and Ho-Oh. What's the extent of Celebi's time ****ery.

Not sure, tbh.

Pokemon is in a weird limbo wherein you have universal + beings and then sub planetary beings right below them. 🙂

Where do you have Mega Rayquaza?

Well if you want to powerscale, Regular Rayquaza was basically able to oneshot Kyogre and Groudon and blow apart a meteor that was going to destroy the earth In a single hyper beam. So Mega's definitely above a good majority of Pokemon.

Also, you were right about the Hoopa thing, apparently he was able to take control over Dialga, Palkia, Giratina, Primal Groudon, Primal Kyogre, Kyurem, Zekrom, and Reshiram through some crazy puppet master haxx. Though ultimately, like the OP implies, the Creation Trio jobs alot in the anime. And it was haxx, not actual raw power superiority.

Still, Hoopa's definitely one of the, probably top 5 Pokemon ever.

Can Hoopa solo SW?

Do you mean like, if every Star Wars character was dropped into a field with Hoopa? Hoopa would die, tbh. Only unsealed Dialga/Palkia/Giratina and Arceus could solo SW. Maybe the Lake Trio, too.

There are also some Pokemon that may or may not be able to via sheer speed, like Mewtwo.

Mega Mewtwo or default?