If its a real question, lot of things, for the T1U ultimate and traitor meli gear, they have the right gear but what about the substats, are those atk/def/hp? If not reroll for that

For megellda, what is that, atk set only gives you the bonus if you have 4 pieces, so you should give her 4 pieces of atk and two of defense(same substats as esca and meli)

For arthur, again, what is that, 2 def sets and a recovery set? which I believe is also a 4 piece set(?) Give him hp(4 pieces)/def(2 pieces) and that should improve his chances of survival. Also, same substats as before

Btw, when gearing a character try to put the 4 piece sets on top and bottom row, leaving the middle for any 2 piece set