Yes, it can be quite frustrating finding info on these boats. And there is no such thing as the world's greatest or most knowledgeable sailor: they don't exist - we're all just making it up as we go along ... ;-P
I can only help you with the following:
1) My boat has a CDI jib furler, with a self-contained halyard, so there is no jib halyard on the mast, although there are four sheaves in the masthead. The main halyard does indeed go through the masthead, and is led aft to a clutch on the port cabin top. I intend to change this setup to a swivel cleat arrangement on the mast for easier reefing. I have no idea what that block by your spreader is for. Something to do with a spinnaker? Dunno, as my boat does not have, nor is rigged, for a spin.
2) I think you mean the jib sheets, and yes, they should run outside of the shrouds (sidestays). Our chainplates (shroud attachment points on deck) are mounted next to the cabin, not out on the gunwales, so this routing makes the most sense.
3) My RS22 has evidence that there may have been other blocks mounted to the deck near the mast base, as well as other fittings (clutches?) mounted to the aft cabin roof, but they have been eliminated/glassed over. These may have been for jib/spin halyards led aft to the cockpit, but I have no way of knowing.
Hope this helps, and if you care to join my RS22 FB page, please feel free to do so, and join the whopping one other person who has!