You have some great heroes, congrats!
I agree with @Chadmo, Malosi is poor on D as the odds of AI using his special well are slim to none. Rainbow D is a good goal, but not essential if the team works well. A 1-1-1-2 team can work just as well.
Based purely on who you have leveled now I would consider your emblemed Boril. Enemies take damage back which I believe would be increased damage if their D is dropped by Athena. I may be wrong in how that game mechanic works though.
Not sure Sabina is great in a flank either, she is a bit fragile. Wing may be best spot.
Good luck though, looks like you have great heroes coming up!