Pregnant Balloon Mollies. Is this the right setup?

I went to the pet supermarket today, and unexpectedly brought home 3 'pregnant' balloon Mollies. I have never kept mollies, but have heard they are pretty easy. I need to know all about fry care and mother care. My setup is a divided planted 10 gallon. The divided side is for birthing moms (nursery), and the other side is where I will keep them. I bought some plant food and supplements, and I also bought some pH strips.
Here's a picture of the strip after being dipped. I don't have much experience with mollies, so is this perfect or stable?

I have a few concerns with this silver Mollie. Is it a he or a she. The employee claimed It to be a female, but Im afraid it might be a male. Does anyone know how far these fish might be in their pregnancy?

I need to know everything about mollies and fry care. What should they be eating, I have some tropical flakes? Ideal climate, and setup? How do I know when they are giving birth?

How big of a tank should the fry be in? I have an extra 20 gallon, and I also need to know what the fry need to eat.

I have been so fascinated by their schooling activity! It looks like the silver one is perhaps dominant, always leading the other two.

Thanks for reading this over. Any answers are appreciated!

 

So, I could be wrong but they don't look pregnant to me. Balloon mollies are normally rather plup-looking so it's hard to tell. You would usually see a dark gravid spot on a pregnant livebearer and they would hide more. I'm not really seeing that on them though I can't be sure from your pictures. Maybe the orange ones but there's not a clear sideways picture of them (someone else might have a better idea).

The silver is definitely a female (look at the bottom fin. if it's a fan-shape, they're female. males have a narrow stick-shape) the full orange one I'm not sure and the half orange one might be female (her fin is covered by the silver so I can't see it fully).

And like most livebearers, they can have lots of fry (20-50 at a time) and will drop fry every 3-5 weeks for up to two months. Balloon mollies themselves get up to 3 inches and if they're anything like platy (also livebearers) then depending on how many fry you get, your 20 gallon might not work for all of them. My pregnant platy had 30 fry in her first batch then another 6 after two more batches (not counting those she ate or were eaten by others).

If you're still planning on trying to keep the fry if they are pregnant, you need to keep an eye out and have a tank ready for separating the adult mollies once the fry are born or they will get eaten. My platy gave birth overnight or early morning. The fry mostly need just clean water and be in a cycled tank. I gave mine small crushed flakes and they did fine in 75-80F temp. I would just be sure to look into care for something like fry and new fish before purchasing them next time.

 

I will be selling the adult fry to a friend. All of the mollies are females, with the silver one clarified as a female. Only one is for sure pregnant, as for the others, I'm unsure. Thanks for responding so quickly!
Here are some better pictures of the one I'm sure is pregnant.

 

UPDATE: just wanted to give an update on the two I think are pregnant. The little orange one, well, I don't think that one's pregnant. The other two have gotten quite large. Do they really grow that fast, or is it from me feeding mosquito larvae? The pictures of the orange fish are both the same fish. I didn't take a picture of the little one since she hasn't changed at all.

 

They all are female. It's hard to tell (even to an experienced molly keeper) wether a balloon molly is pregnant or not. Unless, the eyes of the embryos are shining through the gravid spot. For the shape of a non pregnant balloon molly look also similar to this shape. And with some colors of balloon mollies, the gravid can not be seen at all. That makes it even harder to tell if a female is pregnant or not.
If you're giving them mosquito larvae, they can look bloated pretty fast. That's normal.