well for ur question about shrimp i think the frogs would definitly eat the shrimp as well as anything else that gets in their mouths. if you like the frogs i say throw them in another tank or make somethign to seperate them. the fin nipping can cause lots of stress for the fish and can kill smaller fish eventually. i had a dwarf puffer and he would nip the fins of my roselines and they would be ok. but i would once in a while get a death among my rummy nose and cardinal tetras. at first i thought it was water quality but got the lfs to check and they said all water parameters are top notch.
either way by looking at it a 70 should be able to hold ur stock list as long as you have a good filter. i have a 70 gallon tank with 1 goldy pleco (subadult 8 inches), 1 royal pleco (8 inches), 4 L114 or lepord cactus (all between 6-8 inches), 3 albino bushynose (4-5 in) and about 9 or 10 clown loaches (4-6 inches) the hardscape is a bunch of wood with lots of hiding places so everyone has their territory. it only works for me without deaths is because i got a wetdry rated for 200 gallons using a pump cycles my tank maybe 20 times an hour and an aquaclear 110 (rated for 60+ i think) and i have a water pump that gives a nice flow for my fish
i've been debating on wither or not i should add more filtration.
ok so final word. bioload can be fixed with huge filtration however there's comes a time where the filtration becoems too much (meaning the water flow too strong for the fish) and the fish will get stressed and die. then there's stress levels of fish. more fish = more stress level. you can alleviate this by adding lots of plants and hiding places etc but there's also a limit to that as well. so with what you have i think ur fine. just make sure the frogs mouths don't outgrow any fish (and they should be outgrowing the danios quickly) or else ur gonna be missing some fish. and just letting you know as well canister filters do wonders for keeping water clear.