The above is correct, but can be stated more simply:
4) If a lens goes on a 6008, they go on a Hy6.
No only PQ or PQS lenses works on Hy6.
I tried one old 40mm lens that works on 6008, but did not work on my Hy6.
Yes the Hy6 have nice focus confirmation works also for manual lenses (I don't know how it is on 6008AF), but the price for Hy6 + 6x6 film back will be much more higher.
It is also possible attach sinar digital backs to 6008 AF.
Autofocus lenses is twice so expensive, than manual ones...
P.S. If You planing in future go for MF digital back, than probably it is worth to think about Hy6, if no then take the 6008AF (price / performance).