So should we hold off selling our TRK coins for now or can we sell them if we want (have wallet.dat file saved)?
Hold you TRK until we have the first block.
Does this mean people could still buy TRK and get HYP?
Well right now we are on block 31716 for HYP and TRK is passed that. So right now anything on the TRK chain is already passed that block and won't carry over. We are trying to fork from this block, but I am not going to promise anything.