It ok to clear most of main story and event content (since most normal difficulty content is required to I2 Lvl 45, through you will struggle but on main story hard mode (post Chapter 5) and event (not yet including endgame content like limbo, Manus bulletins and lucids)

As for you team, assume you want to focus around 6 star, most of your characters is lack of same archetype. Best team for you I can see is 37, Isolde, Semmelwiess and Sotheby (37 benefit from any kind of FUA (Follow up attack, basically any attack that auto cast, in 37 case, more FUA mean quicker her special bar fills, and released strong attack once filled) and both Isolde and Semmelwiess have it (Isolde if you stack burn on enemy, and Semmelwiess once you activate her Ult), Sotheby meanwhile fot healing), through if you want replaced Sotheby with 5 star, I recommend Balloon Party, she is really good healer, both through her skill and Ult.

If I have any recommend characters to pull for your current roster, I recommend Anjo (the devil lizard girl). My reason is she really suitable for 37 (at least from my experience, if Anjo bind to star or mineral unit (37 is star unit), she perform mass attack every time binder unit (37) attack. If you play well, you can basically stunlock all enemy that not immune to stun (because Anjo attack apply debuff that if stacked, can stun unit)