I think you just have to make a judgement call on how the fabric will wear. Personally, I'm not concerned that I quilt I make will last forever. F&P recently had an informative show on piecing with diverse fabrics:
http://www.fonsandporter.com/videos-...native-fabrics
They talk about stabilizers. Ideally, you would like the fabrics you join together to be similar weights, so you would stabilize the thinner one. Same with something that's really stretchy.
As far as the bonded wool, I remember when it was introduced in the 60's and we were all horrified. I'm still horrified! Wool is supposed to drape! What I do is deconstruct the garment, then use an iron with a lot of steam and press on the side with the fusible. Usually, this will reactivate the glue and you can peel it off. You need to work in sections. This may also make the wool shrink, but i'm going to felt it in the washer, so for me it's not an issue. You can also use this technique if you are fortunate enough to get one of those fabric sample books. Lots of great fabric, but they are often stuck to a piece of paper.