"Flandre' - Taboo "Lavatein" slows an additional 2%, and stacks once more." is ridiculously broken. 70% aspd/mspd slow (practically a permaslow, about as troll as Letty's ult) is DEFINITELY not something Flandre should have, especially since this item is only 4350 - about 950 gold cheaper than Frozen Frog, and gives better stats.
I would suggest either -
*clones last 2-3 seconds longer
*clones have extra 5% atk
or if you want to keep the bonus for laevateinn -
*Laevateinn gives additional 5/10/15/20 chaos damage per strike.
on the other hand,Kaguya-"Help Me Eirin!" requires 4/3/2/1 second(s) channeling time. seems really weak. 2 seconds is usually enough to rescue someone, assuming they aren't made of paper with only 1k hp. I would suggest an extra 20/30 damage per danmaku pillar (140/210 in total), passive change to 17% + 150 MP, or reducing cooldown of her ward by 15 or so seconds.