Well, I don't know all of the answers, but some of them would seem pretty obvious:
1) I would presume that what keeps AF from simply flooding the market with loss-making routes is a) that they need agreement from their partners, b) 50% of money down the drain is still money down the drain, and c) AF has an opportunity cost - every plane they send across the Atlantic is one that they might not be able to fly to Asia or Africa. Obviously, airlines are very good at losing money, but I don't see why the decisions being made in the JV would diverge that much from the decisions made individually.
2) I don't know. I always thought it was 50/50, but I really don't know.
3) I would presume that we would see this where it makes sense. I don't believe that AF or KL really have a huge presence outside of AMS (where they already do the ground-handling) and CDG (not sure who does it there, as I've only flown on AF there). In other European locations, AF and KL will often use contract ground staff.
4) I believe that AF/KL are the primary point of contact for negotiations for ex-Europe contracts and that DL is the primary point of contact for negotiations for ex-US contracts.
5) I think the first part of your statement is the beginning and the end. It basically amounts to a merger of your TATL operations and brings many of the synergies that a merger would bring.