I actually have an extra Rancor (loose, no Luke or bone though), and a Max/Doda pair carded. If you're interested, I'd sell you both Mosnab. Just let me know.
The Rancor's definitely close, if not dead-on in its scale with the 3.75" figures. The figure's main flaw is that its joints aren't strong/stable. The arms are, but the legs aren't capable of holding the beast's weight up. It's possible to balance the rancor with one hand on the ground and the legs so that it stands well though. I have mine holding a Gamorrean in the one hand, chomping on an extra Wicket I had, and Luke standing before it with the bone.
The Luke figure isn't great, especially considering the new one out there, but it wasn't a shabby figure either. The bone was kind of cool as an accessory too.
They even got the earring in the Rancor's one ear down, which is a pretty minor detail, but a noticeable one in the movie.
The Rebo band pairs were some of the finer sculpted figures of the POTF2 range I thought. Max/Doda were the best IMO, and the biggest value given Max's organ thing, and all. Doda's a really nice sculpt (Max is too), and they look great.
I felt that the Joh/Droopy 2-pack was the least attractive, but it was still a decent set. Sy and Bar'Quin were cool too... Those two sets were the only ones plentiful around me, and the Doda/Max set was non-existant here, but I hear it was plentiful elsewhere so it was hit & miss. I got mine in trades/sales some time ago though and only saw them on shelves one time around here. Kind of like the MMC 3PO. I never saw that thing once, and had to barter for one to get that kickass 3PO. Yet, at the same time, I hear that 3PO was a shelfwarmer some places.
They're all worth owning if you ask me. The Bantha's a superior beast to the Rancor (And sold better as a result) but the Rancor still rocked. The "lifelike" feel of it was kind of cool compared to the vintage Rancor. Vintage's one advantage though, was that it had the chomping jaw that looked just awesome, and worked well to boot. I remember my vintage Rancor eating G.I. Joes left and right. He went from being Jabba's pet to being Cobra Commander's bio engineered experiment. Good times.
So hope that helps...
Oh, and there were instruments for Joh Yowza, and Sy Snootles sold through Raving Toy Maniac's I believe, BUT I'm unsure if they are "legit" repros, or not. I've heard that these 2 figures were originally intended to include an accessory for each. A guitar for Joh and a microphone for Sy... Both are sculpted as if they are to hold something anyway. RTM sold these things for like $3 a set, and they look great. Not sure if RTM still has them up for sale or not though. They're worth picking up if they do though, legit accessories or just customs. They look cool and add a lot to the otherwise more "bland" characters.