You don't need to worry about team comp until later levels, like 60-70 and up.

Treasurewise, like Renji said don't spend on anything but the later treasures. Only do Cloud if you wanna go Lightning main. Kage, GNW and both Jins are all good choices, but I personally think that GNW might be your best bet as of now. It would be best to change your main to accomodate whatever rare character you get from those treasures so that you c*e them...