Sadly, I think you are right that you are going to give one of them up, that is very sad for you.

As you have no way of seperating them and your mum is threatened to get rid of all your pets. I think your female should by the one to be taken to the shelter.

You can always ask the shelter for a male to go with your existing male at a later point. But if you don't act shortly, there will be two litters to consider. Due to the lack of spaces and cages at your house, she needs a new home.

It is good that you are mature enough to take the necessary action. Thinking of you