Those are Reference Two, Reference Three, and Reference Six. The Reference Six is a fantastic speaker equipped with IMG woofers and EMIT-R tweeter. They usually go for $350-500 used, which is a steal. The only "issue" is the cheap looking vinyl cabinet.
The Reference Two and Reference Three are just ok. They still use IMG woofers, but the Polycell tweeters are nothing special.
All IMG woofers will need foams replaced, but I've done dozens of them and they're not much harder than normal. I don't use heat to get the rings off, but that's a good idea. I just slip a utility blade under it, then get a flat blade screwdriver in there and pry a little bit. Do this at two other points and they'll pop right off. The graphite woofer also needs black or clear (like rubber cement) glue. White glue just won't adhere well and will make the project that much harder. Simply Speakers has a nice foam/glue kit that works well.