Help with Formation..

I am level 101, power is 2658716 right now..I JUST got Ophelia yesterday and leveled her up a bit.
My question is formation..can I get more staying power from my team somehow..

I have:
2 Shi Fu, both shield behind sword..so whatever level that is!
1 Adept Rhee, only a few 6 star stones from being Master
1 Allon, Sword and 2 lines behind it.. again, whatever level that is
And Ophelia..2 down arrows over a line..

Any particular way I should order them..I
I am WORKING on getting Marlina as well. And any suggestions for a pink gem hero to go for..I was thinking Candy Can..

Thanks!

You need another tank. Besides Allon,you have no defense. I would suggest going for Breaker Glax before Candy Can. Once you get Oph and Marlina suited to join your lineup, I would suggest Allon and Glax up front and Oph, Marlina and Rhee in back.

Thanks!