Just came back after a few months and finally solo'd Vemosia with trusts for my Wisent Kecks(and chanters shield as I got both on the same kill). Did it with Blackbeard Randy and Amchuchu, Zeid II, Selh'teus, Koru-Moru, and Apururu (UC). Amchuchu tanks it fairly well, the only things that get scary are seedspray doing almost 2k damage and the AoE silence of the WHM running out of MP. Zeid II is pretty decent at stuns which give your trusts a lot of breathing room, and Selh'Teus is great for that AoE HP/MP up move that works even when silenced. Koru-Moru is there to keep Zeid hasted for more stuns, debuffs, back up heals, and refreshing your trusts. Apururu basically cannot run out of MP and I pretty much switched to her unity just because all the other WHMs I tried couldn't cut it and ran out of MP at some point leaving Amchuchu to die alone.
Also make sure you try and wear full 119 the whole fight, the only time my ilvl would drop was when I switched to desultor's for ready, and even then it was just for half a second. Try and position Amchuchu inbetween a wall and the NM so seedspray doesn't annihilate the other trusts. It can get pretty hairy at times so try not to get caught swapping into the pants for ready when Vemosia is about to WS, dropping your ilvl means one TP move puts Amchuchu in the red or the AoE silence lasting long enough to get people killed. Also try to reposition your tiger and yourself to the other side of the monster and absolutely make sure you are 11' away from her so you don't get charmed. I'd suggest not standing in a line directly behind your tiger either as if Amchuchu dies or your tiger pulls hate, you'll get hit with a 1.8k seedspray and die like I did. Just being a little off to the side keeps you from taking full damage and able to survive in regular 119 gear. Familiar helps a lot (obviously, as well as all those delicious gifts) but if thing a go smoothly you won't need unleash or run wild, but if Amchuchu does die don't hesitate to pop them both. Tiger with good pet gear makes it short work, but Vemosia will also kill him back incredibly fast due to all the DoTs so if your pet has to finish off the fight tanking bring a few Mulsums and be liberal with the pet food. Current gear is basic pet ready equipment augmented with pet accuracy +20~ (except pants hence why I'm doing Vemosia) using Akamocchi and standard Pet PDT -4 DT a piece. Aymur + Kerecahtl for ready moves, izozoeksi + pet PDT astolfo for idle, switching to charmer/desultor's for ready. About 259 JP at that time so with those better gifts I'm sure this fight goes really fast.
Good luck and happy hunting!
Also just realized that the Trust Campaign is going on at the moment and they all have 50% more HP. I now feel way less badass, and not sure if this is doable outside that event. Most damage I saw from seedspray was 2000 damage so it probably will be cutting it really close, possibly a different tank like August or Gessho would work.