Roost prevents 'Mence from dodging EQ for a turn. Furthermore, Recovery moves ain't useful in Doubles. You'll lose 50%+ from one opposing Poke's attack, none the less two. Not only that, but 'Mence is better off just throwin' out attacks anyways. Just like Espeon.
Hammer Arm slows Slaking down and lacks perfect accuracy, so EQ spam is still the better option. I'd recommend ya find a more interestin' team combo revolving around STAB EQ spam. A fine example is the good ol' standard Discharge + EQ spam combination. Spamming both moves t' hit opposing Pokes racks up spread damage really quickly. Furthermore, Flying-types lookin' to avoid EQ eat a super-effective Discharge. The strategy works so well since a Ground-type is immune to Electric, so Discharge will only hit the opponent. There's a small variety of Electric-types that also avoid Ground-type moves, Eelektross bein' one of 'em. The Electric/Flying legendaries are a lot better 'course, and should be used if they ain't banned. Zapdos is the most useful in this combo since it gets Heat Wave, although Thundurus-T does hit ridiculously hard. Even with Discharge.
If they are indeed banned, your options are either your current Electric-type or Rotom in one'a it's appliance forms (don't consider usin' Emolga lol). This is one'a the only places where Freeze Rotom is useful, since if the foe resists Electric it can opt t' use STAB Blizzard instead. If Eelektross' Flamethrower is one'a it's highlights, one can use Heat Rotom for Overheat. Wash Rotom is the best of it's forms overall since Water/Electric is fantastic typing, but if ya don't want two Water-types it's Freeze, Heat, or Mow forms are perfectly usable dependin' on what you're lookin' for in the Poke.
As for the Ground-type, just pick somethin' that hits really hard (but ffs don't pick Rhyperior since it lacks Trick Room support). Eelektross/Rotom-Appliance do hit somewhat hard, but Discharge's BP is average, especially when hittin' multiple targets. You'll need a particularly powerful Ground-type to pick up the KOs their extra damage output will allow. For example, I'd say that you wouldn't want your EQ spammer to be any weaker than a Krookodile. Mind you, Base 117 Attack wouldn't be enough t' tackle bulky opponents anyways. Somethin' like an Excadrill or Golurk has enough Attack to abuse STAB EQ properly, not that I'm recommending either of 'em in particular. Just examples.