I just started a 5 gallon tank, what do I do?

Question
I bought a 5 gallon tank and had it running about April 17th. I've added almost several fish.I have a big kong shell in there and a fake plant and I have gravel stones with stones and crystal rocks from pet smart. I have some Mollies/ Ballons and Dalmation version, female betta and another kind I can't remember what it's called. Anyway, when I bought all the fish, didn't relize their couldn't be that many in the tank. I figured, I would give it a shot to see what happens and get another tank, if they were acting arressive. However, they really don't seem to be acting aggressive, they just swim around fast all over the place. So I hope it's ok I keep them in the same tank. I plan on eventually getting another anyway. I was told at the pet store, that the mollies have babies every few weeks..Is that true? Do you think if theres a lot of fish in the tank, that the mollies won't breed or be able to have the babies?
I'm not sure what the process would be. I do want them to have babies, and I would get the other tank. Also, how often and how much should I be feeding several fish, they always go crazy and act hungry when I'm around the tank. Is that normal? Or am I not feeding them enough. I usually feed them 2-3 x per day with 2 pinches of flakes and 1 small pinch of granuals for the betta.
Also, I asked 2 different pet places, on since I just set up my 5 gallon tank on the 17th of April, I added the Cycle and stress coat as directed. Do I need to add anymore of the stress coat/ cycle each week? When should I start doing water changes and how much would I remove? and cleaning the tank? How long do you wait, when you start up a tank and then at what point do you do things differently with the cleaning and water changes? with several fish in the tank. Can you clean tank while fish are in the tank, or do you need to put them in a bowl, while your cleaning?  

Oh the tank also has a filter and wheel and heater and thermastat and air pump and water fall because of wheel, just so you know. I bought the tank at walmart, I was told to change the filter once a month, is that true?

Answer
Hello,

I can't answer the questions about the mollies breeding, because I am not a breeding expert. I can however answer most of your other questions I believe.

You only need to feed your fish the small amount that you give them twice a day. It is normal for them to always act like they need more, but they don't. Their stomachs are about the size of their eyeballs.

You should add Cycle weekly. You should also change your water weekly. I recommend changing around 10%. You can add the Cycle during this change. Regular cleanings (weekly) should being immediately. There doesn't need to be any change in routine from when you start your tank to when it is established. And yes, changing you filter media once a month is ideal. You may want to change bits of it at a time though. Ideally it should have biological media, carbon and a sponge. If you change one of those a week then all your beneficial bacteria won't die. You can clean your tank with the fish in it. This is better because your fish won't need to be put in a bowl with little oxygen, no filtration and potentially bad water.

I hope this has helped and I didn't miss anything.

Regards,
Stephanie