Quiltingboard Forums - new to forum North Carolina

Hi! I'm Karyl McClellan, and just completed my very first quilt top, a Jellyroll quilt (thank you Moda, for jellyrolls!)

I used 2 Moda "Portugal" jellyroll by April Cornell, and I am just thrilled with how easily it came together and how good it looks! How great to have all these coordinating fabrics! Takes away the guesswork (and fretting!) for a newbie like me! It even looks like I knew what I was doing! :-}

I do have a "fret", however..
Can you prewash only parts of the quilt?? Or is it all or none?

...I purchased 100% cotton batting yesterday ("Simply Cotton") at the recommendation of the saleslady in the fabric store. I think I will be pleased with the results of the cotton, and very much like the idea of using 100% cotton (although have been reading here about the 'scrim', which this batting contains.)
My fretting question is whether or not I should pre-wash the batting. I'm just scared to, although the packaging recommends it. The quilt top has NOT been prewashed, as I used jellyrolls, and it was recommended not to pre-wash.
The backing will be a 108" single, unpieced back. (also a Moda cotton, but was really wrinkled and creased from the roll.) In a flurry of 'just do it' this morning, I did launder it, with intent to handwash the batting. But now I am wishing I had waited to prewash the backing and just washed it all together. It is a bit humid in NC right now, and I'm scared the cotton will not dry well.
Do you really get tiny oil spots from the cottonseed/hull remnants?

I have read some of the batting threads here, but am unsure.

Sorry for the long first post!

I have 2 other quilts planned, and can't wait to learn more about quilting~ I'm starting kind of 'old'...be 57 next month! but better late than never.