I don't know too much about pink zebras but the best fish to cycle a tank with are zebra danios they are extremely hardy I cycled my 36 gallon bow with danios.
Also, if you aren't going to keep the danios then I personally think it is best to return them and figure out another way to cycle. If you have a cycled tank all it takes is a little bit of established media or substrate to get things going.
As for the stocking, I would never recommend adding male and female bettas to the same tank except for breeding purposes. Also, two females will likely lead to one of them not being very happy. The females establish a pecking order and the dominant one will pick at the other. If you want female bettas I would have at least 4-5. Otherwise stick to a single male. I agree though about the flying foxes. IME they can be boisterous compared to more peaceful fish.
Could you get a closer pic of the java fern? Doesn't look like normal java fern to me. Also the "fountain plant" (O. japonica) is better known as Mondo grass. Not an aquatic plant so it may eventually rot if kept submerged. I believe the "Japanese rush" is the same way.
1 male betta
8-10 of any smaller, generally non-nippy tetra/barb/rasbora (you can really take your pick on species here)
6-8 corys or maybe smaller loaches like kuhlis or sids
There are a lot of possibilities. It comes down to what fish interest you.
You can transfer over a portion of the media (or substrate) itself. Sometimes even a squeezing will work. Part of the time it takes to cycle is waiting for innoculation. Once the bacteria are established it doesn't take long for them to multiply in good conditions.
how bout i add this with my betta:
7 Black Neon Tetras
5 Rosy Tetras
5 Phantom Tetras
4 Clown Loach
is it unwise to add 3 more female bettas?
so what i need to do is to take a sponge from my other tanks and put it in with my 40g filter?
if i took out a portion of the media in my other tanks, will it not also bring any disease that could've been existing to my new one?