I would buy the HBH frog and tadpole bites asap
bloodworms are ok in a pinch (each froglet should only eat 2-3 at most per feeding) - but you can get "spoiled" froglets and have difficulty switching them. I raise my batches primarily on HBH frog and tadpoles bites with frozen bloodworms used as treats of if I have a VERY small frog morph and I just need the bloodworms to fatten it up so it can eat the pellets.
A gentle filter is okay now - they sell cheap ones that are designed for small fish and fry (baby fish) that work off of a small aerator that would be perfect for you. You can also use ones with thin in-take valves (Whispers come to mind) and cover it with a sponge (cut a hole in the sponge and wedge the uptake in it so that all parts of the intake are surrounded) to prevent the little frogs from getting stuck.