Yes to all of the above.
I prewash everything, I don't leave anything to chance when it comes to that. I always test the block by auditioning it with other fabrics first, that way I can get the muscle memory going and if I'm going to have problems with the way the pattern suggests, I can take some quick notes and figure out a better way to do it. Once I know I've got all of that done, then I'll stitch up a block with the fabrics I'm going to use and see I need to make any further changes before I commit to the full quilt. I have a really bad problem with getting frustrated quick if I'm having issues while I'm working the quilt and if I get too frustrated, I will abandon the quilt altogether and about 80% of the time, I never go back to it. Taking the few extra steps before I start saves me a lot of time and a lot of money.