DID O or X-ring 428 yes
Master links (2) yes
Use the same bolts and tabs....once.
If your gasket is less that one year old you may re-use it if not torn.
My seals are fine at 10,000 miles
Clean the oil filter but unless the oil needs changing don't....Lie the bike on its side for the sprocket change...no oil will be lost.
I have never used Locktite for this type of service. Neither have I used Permatex on the left side case...no leaks in 7,000 miles, but my gaskets came off perfectly clean. Still, can't hurt.
Chain breaker: Motion Pro Chain Breaker - Motorcycle Superstore
Gearing Commander: Gearing Commander: Motorcycle Speed and Drive Train Calculator (Online and Stand alone)
There are TWO critical items when removing/replacing the left case and changing the front sprocket: Make SURE the locating dowels go back where they came from and don't fall out into the case...use heavy grease. Make SURE the stator wires do not get pinched. Because the magnets tend to force the stator and housing to stick, you need to exert force SIDEWAYS BUT NOT MUCH INWARDS to get the outer case to line up. NEVER force it inwards.....Once you have the dowels located the case will go in the rest of the way smoothly. Inspect the stator wires and the little plug just above the sprocket with a mirror and a flashlight after threading a few bolts but before tightening them to be sure they are seated right and not crushed.
It's really pretty easy.