The stroller I have is baby trend since I'm ftm idk I seem car seats at Wal mart with that brand
The travel system I'm using is called graco antiquity and it can be used 10 different ways. You can use the car seat directly with the stroller frame (without the stroller seat) or you can use the car seat with the stroller frame and seat for complete coverage.
We got one that is a stroller and cars eat together.
I don't know about any car seat fitting in, but graco has two lines of products. They are called classic connect and click connect. If you buy a classic connect travel system, or a classic connect stroller, any car seat from the classic connect line fits into the stroller frame and with the stroller seat. Similarly, any click connect car seat fits into the click connect stroller seat or stroller base.
You'd need to check with the manufacturer