1. You can carry a musket while wielding a katana in one hand, but you can't use the musket without two hands, and you can't reload it without a free hand.
2. I don't remember what the deal is in PFS about archetypes and alternate classes, but it doesn't matter here because Luring Cavalier replaces Cavalier features that the Samurai doesn't get, so it's impossible.
3. Quick Draw to go from shooting to wielding a melee weapon efficiently, Rapid Reload to make reloading easier...
Without at least 3 levels in Musket Master reloading a musket is a total mess, since it's never less than a move action. Only one-handed firearms can be reloaded with a free action (Rapid Reload feat plus alchemical cartridges) unless you're a Musket Master.
Without 5 levels in Gunslinger you can't add dexterity to damage with a gun, so it's typically going to be very weak.
Multiclassing a Samurai loses a lot of it's Challenge power - not just in added damage, but also the more important uses/day side of it.
None of this means your plan is bad or impossible, it's just not going to be all that easy.
The thing about the Beneficial Bandoleer is that it works for one load per round (swift), while alchemical cartridges and rapid reload make a pistol or a musket master's musket an infinite free action to reload.
So bandoleer + rapid reload without musket master means you can load once with a move action and once with a swift action, but then have only a standard action to shoot (though you could unload a double-barrel musket that way at a harsh penalty).
With 3 levels of musket master, rapid reload, and alchemical cartridges, you can free-action reload. So you can fire-off a full attack with rapid shot, or you can move and then unload both barrels. Reloading is free.
If you really want to go Gun Tank, I'd consider using a pistol and maybe taking Far Shot. The Picaroon Swashbuckler is a very nice melee-side-option for being able to both shoot a pistol and wield a sword - when you first get into a melee you can fire your gun, reload, fire with rapid shot, reload, then quick draw weapon and use weapon attacks. If you have a double-barrel pistol or a pepperbox you'll have a couple rounds of gun and sword combat before the bullets run out.
No, they both replace Gunslinger's Dodge so they're not compatible.
Honestly it feels like you are over-complicating things; for this build I'd just go Trench Fighter 3 / Dune Drifter.
Alternately Trench Fighter 3 / Luring Cavalier which doubles your touch range with all firearms at level 3. Take Amateur Gunslinger to extend this range, and Extra Grit for a decent usage amount a day.
Trench fighter isn't PFS legal