answer 1
Yes the derailleur and the chainset are compatible. I've just put both on my bike, a Marin hybrid custom tourer, and am most happy with the changes!
As for whether the M771 fits an LHT, to my knowledge this front derailleur can fit many different frame sizes, being adjustable, and I think it also comes with shims, (although I let my bike shop replace my drivetrain as the mechs there did a better job than I would have done). Put it this way, I'd be very very surprised if it didn't fit, it's the most versatile XT front derailleur option.
Check your frame seat tube size, see if you can find more info about the M771 elsewhere online, if still unresolved go ask a mech./tech in a bike shop.
May the wind be in your wheels!
answer 2
These items will be compatible with each other and should fit your frame with no issues.
Number One Contributor
answered 1 year, 2 months ago