Ok, since this is still in the skeleton stage, I'll give you some comments to help you flesh out the body of the analysis.
Starting with the overview, Smeargle doesn't learn every move in the game. There are some moves that Sketch can't copy: Selfdestruct, Explosion, Metronome, Mimic, Transform, and Struggle. I would recommend saying that it learns almost every move, or you can list the moves if you want. Most of them should be intuitive anyway. Mention something about Smeargle being able to do what no other Pokemon can do with its incredible movepool, but how it pays for that access with abysmal base stats.
Set 1 should not be named SleepPass, you aren't passing Sleep. Call it Baton Pass or AgiPass if you prefer. Leftovers is not an item on this set, you must be running MiracleBerry. Moves look good, we try to slash them in order of viability so I would keep your current order, don't forget to explain why each one is circumstantially solid. I think Substitute has moved out of favor since it's very much expected now, but it's still nice to protect yourself against status and Explosions once your Berry's been used, and Spikes are great for securing many relevant OHKOs, most importantly +6 Mega Kick/DEdge Lax vs Cloyster. Encore is nice when the opponent's avenue to stop your sweep is preemptively setting up themselves, and Destiny Bond has a lot of potential value for taking something with you when Smeargle's already done its job. You have to mention that every serious Baton Pass team (assuming you're going the traditional route of passing to SD/Drum users and not some weird GrowthPass) needs to have Jolteon/Marowak/Snorlax, those are all completely non-negotiable here.
Set 2 should just be named Spikes, there's no need to always lead with it, and it can function quite well as a surprise factor when they think you have Cloyster or Forretress instead. You could call it Utility too. I don't think the whole idea of a suicide Spikes lead works very well in GSC, and I've probably tested it more than anyone. So yeah, Spore and Spikes are mandatory, but the other 2 slots are very flexible. Mirror Coat's basically a noob trap, Fear put it best when he said that any self-respecting GSC player is going to scout that. Speaking of which, he had a great set from SPL 9 which used Present and Sacred Fire for perfect coverage against enemy hazard control, with Present destroying Cloy+Starmie and Sacred Fire doing big damage to Forry. I think that set should be the "standard" here, though other choices are certainly viable. Destiny Bond is probably better than Mirror Coat but it's pretty easy to see coming on a utility set. Rapid Spin is an option, you're obviously going to lose out on some coverage but it's very frustrating for the enemy Spiker to deal with when they can't safely come in knowing you have Spore and a 4th move that could be anything. You don't threaten Ghosts at all though, spinblocked to death. Needs Pursuit support for sure. Encore is an incredibly valuable move to have anywhere on your team, and it's risky to hard switch Smeargle into a Cursing Snorlax but if you pull it off you can lock it into wasting PP, get your Spikes up, and phaze it out with no harm done. Smeargle's decent Speed means you can always Encore anything using Curse, and even lock Vaporeon into Growth, Skarmory into Rest, the list goes on. Perish Song is an idea if you're using utility Smeargle on full stall which doesn't have an answer to lastmon CurseLax, Vap, and the like. Still works to force things out, especially if they're asleep. And of course there's Recover, so you can tank Cloyster's Surfs without concern, or not slowly be chipped down by Pursuit Umbreon, that sort of thing. There are so many choices that it can be hard to narrow it down, but that's the burden of a Smeargle analysis. If I had to rank them, I'd say Spore/Spikes/Present/Sacred Fire should be the face of this set, and you can slash in Mirror Coat, Destiny Bond, and Encore, and put stuff like Rapid Spin, Recover, and Perish Song in the set description or Other Options. Worth mentioning that Leftovers can be nice here if you're using something that isn't meant to suicide, pairs nicely with Recover for instance.
Checks and counters: for the BP set, anything with Roar/Whirlwind/Haze/fast Encore/Explosion. For the utility set, everything and nothing, in a sense. Depends on your moveset and more importantly the game state itself. I don't think there's much point going into detail here, being the most flexible Pokemon out there means the stuff that beats you will be flexible too.
I'd love to see this analysis get off the ground, best of luck and don't hesitate to tag me if you have any questions.
