Take the pedals you are comfortable with. My biggest problem has always been braking- I ride skinny tyres (2.1) and I’m a fat busturd, 100kg plus. Braking is an issue for me. I thus need to use bigger tyres and possibly bigger discs. I boil my rear (Avid Juicy 7 @ 185 rotor) unless I’m very careful. I take loads of spare pads with me just in case, plus a bleed kit!
Mech hanger- good idea. There are loads of very good and helpful shops in Morzine and Les Gets- but they do charge quite a bit. The shops at the bottom of the valley in Thonon les Bains are considerably cheaper if you can get there.
I’m assuming you are being guided- take a GPS to record your routes for next year when you won’t need the guides. (and send me the routes too 😉 )
Pad up if you want- not really needed for the XC stuff but it will fill you with confidence- so go for it.
Avoid the Pleney DH! Lemmings galore- up, down, up, down, up, down…
I’ve been out four times now- It’s a great place to go. Make sure you get over into Switzerland too, the trails based around the Mossette lift are sublime, Crossette too.
Have a Tartiflette for me- yummy food.