1) Is this what Eridan was fighting on his planet? Angels? Or at least something like this. He was the destruction class, and these guys thing seems to be destroying universes like it's their job.
The angels were just his consorts. Plus, I'm pretty sure we can take English is an example of a mature cherub; which means no wings, which does not fit the description of the angels.
2) If english destroys the trollverse, is it Calliopes job to destroy the humanverse?
Both universes are already doomed/destroyed by Spades Slick/Bec Noir. If you meant as in a puppetmaster, behind the scenes sense, I think Scratch & English can claim both as is.
3) If Calliope is CAL somehow, then she DID earn her wings to become a feathery asshole, just like Sollux said! But what would it mean?
Wait, when did Cal earn wings, barring his brief stint as Calsprite? Also, Cal's explicitly male (Scratch refers to him as his ecto-father), Calliope is explicitly female (Muse class). Not to mention one's a stuffed puppet and all.
Now, that said; it could be a squiddles/horrorterror thing though... one being a subconcious representation of the other (consider the shape of the skulls, and their coloured cheeks for example). In which case I would say Cal has a lot closer ties to the English side of things. Maybe the name is the only thing keeping Lil' Cal locked away...
4) Lord English hatched from a cal+cueball+guardiancode. What will calliope hatch from to obtain her true form?
Again, taking English as an adult cherub, I'd say Calliope is going to look the same. Maybe exactly if they're the same person (English being adult uu); uu is UU is pretty heavily foreshadowed (logging on or off when talking to each other/names waking each other up/the whole Complacency of the Learned schtick/etc.). Huss may change it up, but my money is on him playing it straight; everyone expects a twist, so he'll twist the twist so much he plays it straight.
5) Do we know of any other jujus that have names that might begin something have to do with wherever calliope comes from?
Closest we have to another Juju is the bunny IMO, and considering the sheer number of names it has had, there's probably at least one syllable in common by pure random chance.