1) Never thought about it but probably said either. Are you asking in case the passengers might know about the aerodynamic 'departure' - I don't think many would?.
2) V1 is, of course, runway dependent. but both will change by roughly 20kts
3) In an ideal world one should communicate enough to keep the other pilot informed of what you are doing, especially if it is slightly (or majorly!) out of the 'norm'.