Look out everybody, opinions coming through. Hopefully I don't come across as too much of a stop having fun guy, I haven't really rated a lot of teams in my lifetime. Perhaps not at all.
Nature: Serious (forgot to save before picking starter)
- Leaf Blade
- Aerial Ace
- Dragon Claw
- Brick Break
I'm not so sure about Dragon Claw here. With Grass + Flying + Fighting the only thing in gen 3 you hit for not very effective is Zapdos, and you might not win against it anyway since all of them have Drill Peck in the Frontier (I don't know about their natures, while Sceptile's base speed is higher and if your IV is good enough you would outspeed them with a neutral nature). Though if you insist on having an attack move there, there's not much else to choose from other than Rock Tomb, Earthquake, and ThunderPunch (or Crunch if you want to breed again). I would put Agility or Swords Dance there myself, since statting up tends to work in the Frontier more than it should.
For EVs you want to max out speed and distribute the rest into Attack and Special Attack (factoring in that your STAB uses the latter).
"Bulky" Physical Hariyama:
Nature: Naughty (was taking too long to find an Adamant one)
- Brick Break
- Fake Out
- Rock Slide/Rock Tomb if not enough battle points
- Knock Off
Naughty is a bit contrary to the definition of 'bulky', but if you're planning to go with what you have then there's not much commentary to be made here, except maybe Knock Off might not be terribly useful since Frontier opponents tend to just have Lum Berries and things that aren't worth spending a moveslot/turn to remove. Putting EVs into HP and Attack would probably work best.
- Rock Slide
Moveset should work quite well if you like Explosion, not like there's much else to put in that slot other than perhaps Roar (depending on your personal preference). EVs here would be a simple 4 HP / 252 Atk / 252 SpA.
EV Spread: 252 Atk / 4 SpDef / 252 Spd
Putting physical Attack EVs on a Timid purely special attacker is a bit odd, so you may want to get that Attack EV reducing berry that I forgot which one it was. You may find more mileage out of something like Agility or Substitute rather than Endure (as you don't have anything which takes advantage of you being at 1HP).
Nature: Brave (Skarmory's catch rate is dumb, and I catch all my Pokemon in Poke Balls)
- Fly (AI is dumb)
Stall doesn't usually work too well in 3v3 matches (the main reason being that you don't have as many teammates to switch in and out of, and because the opponent doesn't switch as much by the same notion entry hazards aren't as effective) and especially not the Frontier, but meh. Whatever floats your pickle. But if you insist on stalling you will want to give yourself some recovery, which comes in one of two forms: 1) Leftovers and Protect/Fly or 2) Rest with optional Chesto Berry. And then you have to make sure one of your teammates can get past Steel types (or Poison types with high physical defense) with special attacks, but if Magneton below does that then you end up with a Fire weakness.
- Hidden Power Psychic Power ~57 (not breeding for a better hidden power)
- Thunder Wave
Fair enough if you don't want to breed for Hidden Power, but there's not much point keeping it on there at this type and level: against non-grass Fighting or Poison types, for example, Thunderbolt does 142.5 damage factoring in STAB and HP Psychic does 112. Having said that, Magneton doesn't have that much else to fill its moveslots with (otherwise I would nitpick Supersonic as well), but there is a bit of AI exploitation you can use here if your Magneton has Magnet Pull and not Sturdy: If you come in on a Steel type (that doesn't have anything which might KO you straight away) and use Flash repeatedly, you can get it down to -6 accuracy, switch to a team member with a stat-up move, and raise your stats repeatedly since the AI hardly ever switches out. Oh, and then sweep of course. As for EVs, max out Special Attack for a start, and then probably HP or one of the defenses. Normally I think you're supposed to put specific amounts of Speed EVs in to outspeed specific things, but without knowing what your Speed IV is (or if it's not 31) that gets tricky. Competitive speed tiers aren't geared towards the Frontier anyway so it wouldn't match up.
Anyways, those are my thoughts/suggestions/ramblings. Maybe you'll have more fun that way or more success, maybe you won't. I dunno.