I have used fleece only once and did not care for it. However have used minky on about 20 quilts. I love it!!
It does come in 60" widths and there is definitely a difference in quality. I usually buy at local fabric store but also have bought at fabric.com. a few time I bought the cheaper stuff, once I ruined my quilt because the color ran, and another time I discarded a piece because it did not feel good compared to the others in my pile. So just be cautious when buying lower quality.
I usually do put some kind of batting. I usually use warm and white but have also used flanalette when making baby quilts. I like something in them though.
I have used pins, lots of them!! but now usually use spray basting, I love it, and never have any issues with stretching or puckers. I also ALWAYS use a walking foot. however I can't FMQ so don't know if that might work for you.