Been waiting this for too long
Interesting quest, much easier compared to mind since if u didn't have yoruichi/ yama it would be such a pain to get to 30.
Liltotto, Oetsu 2x long stride; Blood Chain Ichigo 3x long stride (Kon link). If you have the Soul Reaper charm then replace the Heavy Bag/ Speed Ball.
All are 2/5, no proficiency slots since I'm too lazy to roll. But if you can then make sure you do so, it would be best to roll an extra long stride to make it faster.
Try to oneshot the first waves with 1-2 strong attacks to save time.
I chose these 3 because Lil offers 30% sp, Blood Chain Ichi has Frenzy 4 + great Ex, Oetsu insane damage output with the best gauge recharge.
Alternative: 10th Anni Rukia, Ss Noel, 9th Anni Kenny, Bankai Yachiru, Parasol Macy (goated 20% team/ party recharge but dull SA1).
Hope that helps!