1 - Yes, once you get the TradeFortress BTC you can remove the trust line to him, and you will still hold 1 TradeFortressBTC. If you ever send bitcoins to somebody who trusts TradeFortress, the client will use the TradeFortressBTC before using BTC from issuers you still trust.
Is there some Ripple address maybe some throwaway account that trusts that TradeFortress account we can send these useless RippleBTC to that are otherwise inflating our genuine Ripple balances?