Okay you have shida. Here is your frontier hunter strat until the end of time: put shida on your team, fill team with high hit count units, at the beginning of first turn of each floor in the terminus cast shida sbb, sbb with only enough units so you don't 1 turn kill any enemies, kill everyone on turn 2 using shida's bb if you are lazy like me, wait until turn 3 if you want to maximize points. No level should take more then three rounds.
Your team should have, shida, darvanshel, lario as staples. Add exhvel if you have him for status null. otherwise lead griel. Elza fills in the 5th slot assuming you have no feeva or ruby.
Elemental weakness damage is king of fh points. Weak + sparks+ 3 turn kill bonus= collect fh ranks. Mid farming is popular right now, but it has been nerfed in jp.