Just cleared Sandalphon for the first time with Awoken Meimei + Verdandi. It was surprisingly close too - I rolled Uriel on floor 3 and althoug he did keep giving me hearts this team's RCV isn't anything impressive and since Uriel is fire I couldn't count on my defenses. It was super close though because he decided to bind GZL twice in a row which meant that I couldn't activate. I brought him below 50% and he started spamming his "turns hearts away" attack which literally put me at 216 HP once GZL was out of the bind.
After that though, it was smooth sailing, Raphael went down super easily, and although Sandalphon did end up turning my dark orbs away a lot, it was fine - there was a point where I dropped below 9k health though, so a Sword of Malkuth would've killed me, alas, between Liu Bei's heal (yes I used his active exclusively for the Heal :V) and a Verdandi board which gave me a whopping 15 heart orbs, I got out okay.
This team is super fun to use too, easy enough activation and a whole lot more damage than it has any right to, rofl.
(I just wish I had Kaede to put in the place of Leeza, then this team would be perfect.)
So now I need to get around to beating Beelzebub (super easy with Athena) and Hera-Beorc (should be doable with Awoken Meimei) then I'll already consider this Descended Challenge 100% profit.