Yes, it will be pre-farmed. I imagine the MaidSafe dev team will configure that all manually in their own vaults right in their internal SAFE network before the official launch, and when it’s all set up as intended it gets opened up to the internet. That’s the moment of launch, and everyone can then connect and join that SAFE network. Network ‘churn’ will then automatically start taking care of spreading that data from MaidSafe’s vaults over the entire public network.
As for the 10% that is currently represented by MaidSafeCoins, I think that’s all in an account of MaidSafe initially. They’ll probably run some sort of server with a program on it that monitors the MaidSafeCoin burn address, and to which you can in advance tell from which address you’re going to send MaidSafeCoin and to which SAFE account it should then send the corresponding SafeCoin.
Anyway, I believe that’s the gist of it. I might very will have missed or be wrong on certain aspects of it.