Is it possible to remove the bars next to party members names?

[Mimilu]

They're called cast bars. They only show up when a partymember uses a spell.
As of right now, no, there isn't a way to remove them.
Granted, if-and-when you get to the point where you do full party content as a healer, it's a nice thing to have so you can see what your co-healer is doing.