2-BTC and BCU will be seperated like any other altcoin after hardfork no relation for price.
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Mostly yes - but there is one tricky part - see www.reddit.com/r/Bitcoin/comments/4vbsgi/what_is_replay_attack/?st=j0i9ilgc&sh=fe729ee7
Apparently there is no transaction replay protection planned - so everybody will need to do it himself. If there is a fork and you have your old BTCs - you first need to send both BTC and BTU to addresses that you control, then use them as normal. If instead your first transaction will be sending BTU or BTC to some external address - then the receiver of the coins will be able to copy your transaction to the other chain and also get BTC or BTU respectively.