#2 is a personal preference.
If you have the time and patience, there's nothing wrong if you do.
I stopped washing fabrics about 8 years ago. I couldn't believe how much additional time I had to sew. And I mix and match pre- and post- fabrics in the same quilt all the time.
The only things I wash are some international fabrics (African, Japanese, etc.) which aren't commercially produced.
I NEVER use white fabric, but that's a matter of personal preference.
However, I've never had a problem, and ALL my quilts get washed. Repeatedly.
Again, YMMV.