Many of the hair extensions and the wig hairs suffer from the same syndrome as many commercial synthetic hairs: they felt. This doesn't go for all colors, kinds and brands, only some. You will have to test them before using them extensively. But that's also the case with what you buy in fly shops.
Regarding the rest of your advice, you are so right as we have already covered in several articles like these:
Inexpensive materials
Wash-n-Dry Dubbing
Martin
