You seem to have pasted your water adventurers twice instead of your fire adventurers.
Your teams are largely what people would recommend; a DPS, a DPS or semi-support, a support buffer, and a healer.
The rest largely comes down to personal preference; some people would tell you to put a sword in every team to speed up breaks, some would say you should have a Blade and a Wand in every team to maximize coability coverage, that sort of thing.
Mikoto is a bit old, if you have Sarisse or Chelsea, one of them might be slightly better DPS.
Xain was never that good, consider promoting Orsem or HOdetta. There’s also Karina. Make sure Aeleen is built enough that you can swap to her if you’re fighting stun.
Melody is fine, and having the Blade coability on her means you could use Ku Hai or Louise instead of Addis. That said, she’s basically been completely replaced by Noelle in high difficulties. Try and get WElly or Victor. Wedding Xania is the anti-freeze healer, not that we’ve even had a water freeze event ever?
Light is fine, but gosh darn it man, promote your units. Get SCleo and maybe Zardin ready in case we get something important that’s immune to paralysis.
Dark is great, but watch out that Delphi is half useless against enemies that can’t be poisoned. I have the same problem with not having either Heinwald or SVerica, Hildegarde is still the best healer AFAIK.
The highest tier you can muster is going to be the best, assuming ‘general use’ to be unaffected by any bonus damage passives.
void 4* < core 4* < void 5* < core 5* << HDT weapons <<< t2 HDT weapons
For wyrmprints it’s basically
Resounding Rendition < weapon specific print
for the first slot, then something adventurer-specific for the second. Skill haste is really breakpoint-y and so adventurer-dependant. Support buffers want From Whence He Comes or Beach Battle for water. Healers usually get Give Me Your Wounded, but Cleo’s Ruse is fine for non-HDT missions.
Dragons are really important, don’t ignore them. Skill damage is better than pure attack, outside of minmaxing for HDTs. Freyja is better than Garuda for wind healers, otherwise put skill haste on your buffer. Mini Mids, if you were around for the anniversary, is 30/30 and level 100 on any adventurer.
If I’m overestimating how many dragons you have, the single-stat 4s are fine to use until you have a similar 5 max unbound or three unbound. Specifically I mean Ifrit, Roc, Vodyanoi, Juggernaut, and Unicorn on Hilde. The greatwyrms you can get from dragon trials are worse than the gacha 4s, but Brun and Zodiark are fine as the only pure attack dragons of the five. The high dragons are only 30/30 at max unbind, so they’re equivalently worse than the gacha 5s.