If the wool pieces you are washing tend to bleed a lot I would not use it. If they shrink a lot I would not use it. It does not have to be felted. The old crazy quilts had wool, velvet, and different siikies including ties and ribbons. Most of those were sewed directed onto a piece of light weight muslin or cotton. Some were then high lighted with the various stitches at each seam, helping to hold the seams in place and preventing the unraveling. Check on the board here for some of the Victorian crazy quilts for some ideas with using your wool. I am planning a tie quilt with names of the men in the family and I will have to remove all the inside of the ties before I wash them. I just saw on here a dresden plate with the ties and it was just wonderful. When you take the arms out of the jackets, you should get a good bit on fabric. Have fun and don't worry too much.