Why would it have Attract? Just because Iris's Emolga has Attract, doesn't mean Elesa's Emolga will. Thats like saying Trip's Servine/Serperior will get Attract.
So we have no Pokemon that are guaranteed to be used here. I don't give a rats ass if Pikachu was used in every Electric Gym. I am pretty sure Tepig is out though. I think 3 gyms in a row is enough. Besides, I don't think it can do much with Tackle, Ember, & Flame Charge. Then there's Oshawott, I hope its not used. And I am hoping his battle against Stephan was his "Electric Battle". Tranquill should also sit out. Not sure about Scraggy, its getting stronger but most baby Pokemon don't get much battle time. Ash's Phanpy only got an unofficial battle against Pryce & one league match. Dawn's Cyndaquil only got 1 contest & then the Performance Round & 1 Battle Round in the Grand Festival. May's Eevee got 1 contest and then 1 Grand Festival battle. I wouldn't be surprised if Scraggy sat out until the last 2 gyms, which I wouldn't mind, but only if it gets some non-gym battle victories/losses in the meantime.
That leaves Pikachu, Snivy, Palpitoad, Swadloon, & Roggenrola. If Roggenrola isn't used until the 6th & 7th Gyms, then I wouldn't mind if it isn't used here. Palpitoad & Snivy should be used for obvious reasons. I am pretty sure Ash's Don Battle Pokemon are his choices. I also believe Palpitoad will be used in only one gym. If I had to choose, Swadloon could sit out until its used again as a Leavanny in the Ground Gym.
We haven't seen Roggenrola in a long time, and if it does fully evolve, it's going to a very quick evolution too so I'd like Roggenrola to get some battles in before the next time it shows up resulting in evolution.
Now let me do an analysis of the Pokemon Ash has:
Pikachu: HELL NO! Well okay true Pikachu has been in electric gyms before, but I want Pikachu to not take place. I still only want Pikachu in 4 gyms, and it's already technically been in two. And it sure as hell is going to be used against Skyla no doubt. Especially with her Swanna. So no, unless magically Pikachu doesn't end up being in a gym after Skyla I don't want to see it in this gym. Besides Pikachu wouldn't exactly be useful outside of Emolga.
Tranquill: Well if Ash was ever going to use her in a battle, it would be in this gym. Ash has used disadvantages before, most likely to throw his opponent off. And I'd really like it if Tranquill managed to beat an Emolga. But since Ash isn't using Tranquill for battles, it isn't going to be used. Especially since it has no neutral attacks against Elesa's Pokemon outside of quick attack.
Oshawott- Hell no, the only starter Pokemon I want to see in this gym is Snivy.
Tepig- Same as Oshawott
Snivy- It did get a nice win in the Don Battle Tournament, but more of Snivy is better. So I'll be hoping Ash uses Snivy since it hasn't gotten a gym win yet.
Scraggy- NO, I don't want Scraggy taking a slot just to lose, I'd rather Ash use a Pokemon he hasn't used hardly at all and the Pokemon loses because it wasn't quite able to beat it, over a Pokemon who loses because its not quite on the level as the other Pokemon.
Swadloon- Originally I would've been for this, when it was just Ash's six Pokemon + Sewaddle but Palpitoad and Roggenrola throw a wrench into that. So that being said Swadloon can sit out for Snivy.
Palpitoad- The only reason why I doubt this is for two reason. 1. Palpitoad was most used in the Don Battle Tournament. 2. Palpitoad would be largely useless against Emolga unless it learned another attacking move because Hydro Pump and Supersonic alone isn't going to beat an Emolga, and I don't think it'll beat Zebstrika. It could be used to be the fall guy but I'd rather that be Pikachu if its used.
Roggenrola- Roggenrola is arguably, no definitely the best choice against Emolga. And I think this would be a very good opportunity for Roggenrola because it would be its first battle.
My top choices are: Snivy, Palpitoad, and Roggenrola. I don't care who wins what but if at all possible I'd like each to get a win. But like I said Palpitoad is going to need a new move if it wants to beat an Emolga. That said I wouldn't mind Roggenrola sweeping the two Emolga and have Snivy beat Zebstrika with Palpitoad being the fall guy.
But we all know the writers don't know how to write battles, and they would have Pikachu battle a Golett with just Iron Tail at its disposal even if Ash had a Palpitoad at his disposal.