Most likely Bitcoin's value would increase compared to the Dollar, GBP, EURO and other fiat currencies. It would be seen as being more stable and the value increase would entice others to get some. I doubt it'll fall as it is not fully reliant on the US economy to keep it going.
The value of the bitcoin will rise compared to the fiat. If the fiat crashes, the bitcoin price will rise even faster.
I think so. That is the reason why I have bought the bitcoin in the last few years and keep them for the long term.