If it were me, I'd bite the bullet and purchase new hoses. You may or may not be able to remove all of the crystalized Iso, and I would think the likelyhood of stray crystals clogging your gun and causing a restriction and an off ratio foam would be something you wouln't want to gamble on. That can be frustrating, and very expensive.
I'm not sure of compatability, but have you checked with other manufacturers about their hoses ? I use Glas-Craft and I really like their stuff, and I don't believe their hoses are quite that expensive. If you'd like the number of my distributor, or the factory, I would be happy to pass it on. Matt