Since Kirin teams are mostly made up of Echidna + orb changer + gravities, then I'm thinking U&Y would do well with the same
Hera-Is/Vamp for dark
Zeus/Valk for light
although since U&Y have orbchanging actives I would say take gravities over heartbreakers, especially since U&Y are getting skill ups soon-ish
ADK is good for killing fire and functions like Verche on Kirin, same with Siren
Venus is amazing for combo teams, and if you have a dark/light venus then theoretically you could run whatever the fuck you wanted for the other three subs, including echidna
U&Y, Venus, Orochi, Hera-Is, Zeus would probably be optimal for big boss descends. 5 turn delay + 2 gravities + U&Y active + Venus to make a gigantic x25 combo could probably easily kill two Satans. You can replace Orochi with Echidna or Siren to make all that stalling. Awakenings are generally irrelevant for this team except for having auto-heal and skill boost on Venus to help stalling for those gravities.
U&Y, ADK, Valk, Vamp, Siegfried would probably be good for general farming since you have an orb changer for every element, helping ensure you get x25 attack every turn.
U&Y, Athena/Valk, Hera-Is, Echidna, Bastet is literally the perfect monster team if you know what I mean (like holy shit it actually works perfectly)