I think, I WILL rate it, seeing that you've posted a couple and nobody has rated. So!
Crawdaunt: Okay, at first glance, I'm thinking "What are you doing with dragon dance AND swords dance" and I'm realizing that you might as well have both. After all, with adaptability, and crawdaunt's fairly poor moovepool, not much really overpowers a waterfall or crunch on crawdaunt. HOWEVER, pointless is pointless, so I'm just going to take out Swords dance, keep Dragon dance, and give Crawdaunt here either substitue or knock off. Since you don't really have anything that will provide more power, go on ahead with these options. Substitute gives you an extra life/ turn to set up, whereas knock off takes off bands, scarfs, and other annoying items.
Cofagrigus: I don't use this guy a lot, but it's a good set, and you should definitely use it. If ever you find HP fighting is just too weak, you could give him good ol' toxic, or psychic for some alternate coverage. Pain split is also usually an OK option on walls and other annoying ghosts, so I don't see it going horribly wrong on Cofagrigus. He really looks good, and you should probably keep him that way.
Rotom-M: You never can tell these days: To trick or not to trick? That is the question. In RU, lots of tanks like Tangrowth, Escavalier, and Magneton hate the tricks, so typically Rotom-M is good with this. He isn't bad, and I'm not going to push you to switch him, but since RU has some really nice grass types, I'm going, to give you some other options.
TANKgrowth (Tangrowth) @ Leftovers
EVs: 252 HP/ 252 SpD/ 4 SpA
Nature: Calm (+SpD, -Atk)\
This set is good to stall, and make the opponent regret setting up on you because, well, they'll be asleep. HP rock makes Moltres think twice about switching in on you if you can predict that.
Sceptile @ Life Orb
EVs: 252 SpA/ 252 Spe/ 4 HP
Nature: Modest (+SpA, -Atk)
Here's your special attacker. He's fast, strong w/ modest nature, and doesn't need to set up. He outspeeds the Scyther's, and obviously the Moltres and kills them with HP Rock. Some people will tell you to go with a physical set, but I feel like, with his special attack stat that physical moves would be disappointing. This guy's spread/nature/moves can be bent to fit your needs, but this would be the set I use.
Roselia: OK, well, you already have a grass type, I'm going to suggest some other pokemon to get up entry hazards.
Omastar @ Leftovers
Trait: Shell Armor
EVs: 252 HP/ 252 SpD/ 4 Def
I'm expecting you to change up this guy a little. You probably won't need all 3 entry hazards, but you do seem to want some. Omastar also deals with your rock weakness nicely. Forcing fire types to switch can be a nice time to get up some entry hazards.
Cryogonal: I actually like this set. As much as I hate Cryogonal, this one seems like it might just work. Haze is good for the common Sword Dancing, Dragon Dancing, Calm minding, and Nasty Plotting pokemon in RU. Rapid spin is a good idea for the entry hazards, as they are also numerous in the RU tier. Overall, he looks like a good special wall and I hope he works for you.
Munchlax: LOL! Strait out of smogon onto our database page here. OK, he's good, but, thanks to me, you know have a Fighting weakness. Though Cofagrigus walls them for the most part, you should have a back-up plan. So now I think I'll show off my latest poke who has served as my RU MVP in the last several RU battles I've done.... I present to you!
Scyther @ Life Orb
EVs: 252 Atk/ 252 Spe/ 4 HP
Nature: Jolly (+Spe, -SpA)
He works like a charm, outspeeding the smogon Sceptile set. Areal Ace gets STAB and a technician boost, so I like it more than acrobatics since he gets the life orb in the package. If one swords dance is used, then you're ready to take out a huge chunk of the tier! He also takes fighting like nothing, and since fighting type moves do 1/4 damage, they might as well do nothing. I hope you like him!
Have fun in the RU tier!!!