Also, let's say XCP dies or we decide XCP is not a good fit later on, will you be able to migrate to ETH or another blockchain?
Obviously the answer to this question is yes.
Is it not possible to track this via escrow address on blockchain?
There is 1 Bitcoin address, and thousands of addresses for each coin.
I'm only a small fish: is there a minimum amount of BTC, ETH or other of the acceptable coins I have to send to the relevant address in my account on the logged-in NVO crowdsale website? In other words, what's the minimum contribution/'investment' amount for me to participate in this crowdsale? e.g. 1 ETH minimum, 0.01 BTC minimum, etc?
There isn't one, however do keep in mind that you should not send very small amounts that would get eaten by the transaction fee. I'd suggest a minimum of 0.01 BTC as you've mentioned.