Good questions, the plan at the moment all testnet data will be scrubbed (we are running a ton of randomised data at it just now). In beta then it will persist.
As far as safecoin then we will have test_safecoin in testnet3, we will use this to try our hardest to attack the network (reliability and any attack vectors) and invite all comers to do the same. During BETA we will go live with safecoin real. This will give all farmers an idea of farming rate and it may seem unfair to lose test_safecoin (I am not sure we could not work out a way to keep or transfer these) but in any case the rank and storage will be good. This means you may have worthless test_safecoin, but the real safecoin will get farmed much faster by existing farmers, so it should definitely be worth it.