Re the Capt's rest,
With 3 crew to operate this long sector that exceeded the FTLs for 2 pilots the capt is required to take a rest period.
If it was his sector it is perfectly reasonable that he should take the middle rest period. The company AF provided him with two 'qualified' pilots to ensure that he could take that rest period. The ITCZ transit should have been, and on previous transits probably had been, less of a hazard than a early morning, tired arrival at CDG. Thereby avoiding an AMS/THY scenario.
Without the benefit of hindsight, most longhaul captains, that I have flown with, would have taken the same rest period if it was their sector.
IMHO it was a reasonable decision; I would almost certainly have done the same. OK we don't know his assessment of P2 and P3 from the outbound sector. In some roster patterns he may not have flown outbound with both of them.