Gimmicky? :o this is good by the DB's standards, lol. Well, it's going to be difficult to answer if you want to keep Spinda THAT badly, but I'll work with what I have and I'll do my best to give a good answer xD. Anyway, let's go!
Spinda... smh... well, it's your funeral! ;] Anyway, from what I see you'll be Tricking your choice scarf away immediately, as it will be useless with no Spd EVs. So that's fine. You'll want to have 252 HP / 252 SDef / 4 Atk Careful Nature though, as you won't be outspeeding much and you'll be able to tank more special hits (kind of :/) before retaliating. Also, Rock Slide is useless coverage, as Superpower and Sucker Punch hit everything in NU besides Champion Croagunk. So, as your team has a rather annoying Rocks weakness, I'd replace it for Rapid Spin. It gets STAB too, so something will take a heavy hit! >:D
I like it. Golbat is actually pretty good in NU, he has solid bulk as well as excellent speed for a defensive pokemon. Replace Brave Bird with Super Fang, it will do nothing anyway with 0 Atk investment and base 80. Plus the recoil is counter intuitive for a wall. EV spread should be 252 HP / 176 Def / 80 SDef to take hits from both sides a little better.
salac berry... you have extremespeed... why :/ Replace it with a Sitrus Berry, otherwise you'll be killing yourself with Belly Drum more often than not xD also, you're dreaming if you think Linoone can set up a Substitute AND belly drum. One is enough. So give it Seed Bomb, to get a harder hit on Regirock / Golem etc.
You have a baton pass moveset, but nothing to baton pass, lol :P Besides, Volbeat is not great in NU unless on a dedicated Baton Pass chain. If you want to keep it for the gimmick factor, put in Tail Glow instead of Roost or Substitute. Otherwise, I have a replacement:
Electabuzz (M) @ Choice Scarf
Trait: Vital Spirit
EVs: 252 SAtk / 252 Spd
Modest Nature (+SAtk, -Atk)
- Hidden Power [Ice]
- Focus Blast
- Volt Switch
You said you needed another Special Sweeper, and Electabuzz is pretty good. I would have suggested Rotom-S who has a handy dual STAB and immunity to Ground, but then your Ice weakness would have been rather hard to handle. Anyway, to the set. Choice Scarf lets him revenge kill and sweep. Thunderbolt is STAB, Hidden Power Ice is pseudo Bolt-Beam coverage. Focus Blast hits Thick Fat Piloswine and Magnemite, as well as the many Normal type special walls in NU like Lickilicky and Audino. Volt Switch is STAB and lets you scout for switchins and send out the appropriate counter :]
Awesome and original moveset. Is helped a lot by spin support from Spinda, too. No suggestions.
One word. Technician. This awesome ability gives you a boost to lower power moves like Charge Beam, Icy Wind, Magical Leaf etc. Replace Thunderbolt for Icy Wind, and Energy Ball for Magical Leaf. Charge Beam isn't that helpful since you already have Electabuzz for Electric type coverage. Also, what's with that EV spread? 252 SAtk / 252 Spd / 4 HP will benefit you a lot more.
Well, I'm done. Thanks for posting such a fun team to rate, and I hope I helped :D