That's a beautiful fleece. In addition to the pattern and colors, it's great how the majority is light so you can pick up on health issues more quickly (blood, messy poops, etc...). Nice find on the silver/grey igloo too. I haven't seen that color before. I'd swap the t-shirts out and put some fleece in as a replacement. Their little nails can get caught in the threads/stitches in the t-shirts.
So, right now, they're both in that one while you fix up another? My thoughts run in two directions at once: (a) it's early in your hedgehog ownership, so probably not the best to be breeding yet, pull her out now and hope they haven't mated and (b) well, they've probably mated, so let's set those concerns aside at this point and make sure all bases are covered.
Thinking about the cages, Momma-to-be should be on a substrate... like shavings. NOT pine. Because once she has her babies, you cannot disturb the next for ~6 weeks and leaving fleece for 6 weeks is going to get pretty rank. Are you planning on moving her to the smaller one? Or moving "dad" there and swapping out the fleece for substrate bedding in the big one? Either way, you'll want to make that transition sooner than later so she feels comfortable in her new environment before giving birth.