In 100% of my experience it's the driver's side tensioner which fails first, and its really only possible to tell what state they are in when they are out of the engine.
I'm not entirely sure what you're seeing on the passenger side - normally the exhaust cam jumps forwards when the belt is removed due to the position of the lobes acting on the valve springs at TDC. Perhaps it jumped forwards and took the inlet cam with it, and then you wound it back and it hasn't tensioned the chain?
There are two failure points in the tensioners. First is the cold start pin - if this is working then with the tensioner removed one of the shoes will be locked in place and the other will be under some spring tension. If this isn't working (ate the gauze) then both shoes will move. This isn't fixable and needs a replacement. Its always the driver's side which goes first as the pin is at the bottom on the driver's side so the gauze drops down the inside and gets pushed through the pin. On the passenger side the pin is at the top so rarely fails as the gauze drops to the bottom and never gets to the pin.
The second failure mode is the non-return valve in the base of the tensioner which provides initial tension on startup. A good tensioner will not leak oil out of the base when removed (non-return valve seating properly) whereas a bad one will constantly dribble oil, especially if you work the shoes up and down. This will cause a little rattle on startup but is generally acceptable. Again, usually the driver's side first but for no obvious reason this time. It looks from your pic that this may have failed on the passenger side, but you can't necessarily see it on the driver's side as the tensioner is the other way up.
The RS6 guys seem pretty convinced that the Vaico units are in fact the original Audi units but without the £300 Audi rings. Chances are next time I need a set I will go with those.
I've also heard that the BGA units from GSF are also the Vaico units for £150 trade, but as I don't have an account with GSF I've been unable to verify that. BGA don't list anything for the S8 but they are the same part as the A8 4.2 which is listed. Retail from GSF is the same as the Vaico from Autodoc though.
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