They're hexagonal ceramic thermal protection tiles for re-entry. It's thought these are based on NASA's TUFROC, which SpaceX signed a Space Act Agreement to access 2 years ago.TUFROC is used on X-37B, and will be used on Dream Chaser. SpaceX will no doubt formulate an enhanced TUFROC-X version like they did with Dragon's PICA-X heat shield.
SpaceX has been testing several attachment systems ranging from adhesive or snap-on to pins of several typss. A few fell off, so that system goes back to the drawing board.
The black cylinders are COPV's containing methane, or cold gas for the reaction control system.
SpaceX Resorts?
https://boards.greenhouse.io/spacex/...jid=4816599002