1) I seem to remember there's a kind of a tight-fitting sleeve bearing inside the block so that the blade could rotate about its long axis (feather). I think there actually is an old retired star floating around here somewhere here at work getting rained on and so forth. The tips of the stars sort of reshape into a cylindrical cross-section for insertion into the block.
2) Well, we called them "frequency adapters" but from what I remember it was an elastomeric compound that flexed to provide lead/lag.
3) I think the composition has changed over time to improve durability. I seem to remember they were some kind of composite synthetic rubber stuff with some carbon thrown in there, but I'm not a maintenance guy, I just fly the Dauphin (same head basically, just another blade).
4) I don't think so. You drop one on the concrete, it will bounce a bit, and you can very slightly dent them with your fingernail, they're softer than I imagined they'd be. I don't believe there's any thrust load on them at all. If you look at the blade grips, they're very herky in linear compression and tension. The blade retention pins (the thick dark vertical pins) are serious hunks of metal and are supposed to be pulled, cleaned, inspected, lubricated, and reinserted quite frequently (I don't know the interval) They're quite strong in shear. I don't remember how the grips are attached inside the head, but if I hunt around, I might find an illustration.
RVDT- Thanks for that, couldn't remember the way the bearings were set up. Actually, I think once you understand how the old heads work, more or less, the new ones are easier to understand. While I haven't flown any of the heads you illustrated, it's easy enough to tell what all the bits do (or don't do).
Sleeves, grips, all one to me (probably a bad habit from Bells, where the similar bit is called a grip). We spent the better part of a decade peeling off all the French warning labels on Le Dauphin and replacing them with Anglais "the Dolphin".