How do you know unless you ask?!!!
So there is not a one answer to that question.
One big problem I have had, and others as well is that the little fish can die in their net from less than perfect water quality. Their fish food just stays in the breeder net and doesn't circulate very well and degrades and can kill off the whole bunch. I know this because it happened to me more than once, even trying to be careful. Especially made harder by having a large number of them in there.
So food for thought.
These fish are live bearers and they have a zillion babies, because in the wilds, a huge number of them are eaten by predators. They will have more babies.
Guppies store sperm from their male companions and can have babies 6 months later. I have had a couple thousand babies since January
The short part of the answer is if it can fit in the bigger fishes mouth, they can be eaten and cover, intake tubes. (but my little ones have stayed out of there) some tubes are covered and in some tanks they have a huge canister filter thing like a hand sized pod to suck up water.
What I have seen id momma Guppies get REALLY aggressive for food. I had Platy (similar, but not the same, they were pretty easy and didn't really seek out babies to eat) but not kept Mollies, though I feel like I have heard they are a bit pushy for food as well.
You might try saving about half of the both kinds of babies in the new and let half free range in the tank. Get them some easy to grow (like a weed) in your area, a frilly/ leafy stem plant and plant some and let some float and give the fry extra places to hide - or fake plants.
A dollar per gallon sale Petco tank or a used tank might be a better solution for the Guppies, more space. Guppies can be kept around 75F and do not require an air bubbler but might do better with it. Or an internal filter, something to turn the water.
The babies love food and need to be nibbling many times through out the day and therefore need cleaner water since food is used so often.
Back to the breeder net, I now would take cups of new dechlorinated (always) water and gently pour it directly into the net AM and PM. This helps the older water circulate through and extends survival. imhe.