Is this a good 55g, or should i upgrade to a 75g?

[sholi]

-1 kissing gourami
-1 6inch gourami
-1 angelfish
-1 butterfly fish
-4 silver hatchetfish
-4 cories
-6 skirt tetras
-1 african featherfin fish

So my questions are:
~are these fine in a 55g? or will i need to get a 75g instead?
- if i need a 75g, can i add 6 more skirt tetras?
- if i cannot add 6 more skirt tetras, can i still add anymore fish?
~will the catfish sting(or stab) me when i am vacuuming the tank?
~Do butterfly fish bite hard?
~are any of these fish sensitive to medications (like parasite guards)?
~and lastly will there be any aggression?

Thank you so much!!!!