Help! Sewing fitteds

[babyike2011]

Ok, so I am a completely novice sewer but I have been making some fitteds for my dd and the newbie due in a few weeks. My mom decided we need to do some farmers markets this coming spring (she does aprons) and I have a few questions.

1. What is best for the outer? Knit or flannel?
2. What about the absorbency? Sewn in or snap in and what should I use?
3. Inner layer (against baby) can be anything, right?

I have made some flannel fitteds and some T shirt ones too. I have just guessed at the soaker layers an used recycled flannel or knit, oh and some flour sack towels. I sewed most with a hidden absorbent layer and then a lay in doubler. I just want to practice and make something nice but not über expensive. Thanks ladies (and any gents)!!!!!