Is my team good enough?

Hey there, just registered here.
I started playing my sapphire again and I wanted to share my team with you guys and ask for opinions and a few questions. To start off, here's my team.

Kyogre-46
Blaziken-48
Gardevoir-46
Flygon-45
Altaria-45
Shelgon-38. (Priority training before E4)

Well, that's my team. Some of them are under-level for elite four. I am now trying to train my Pokemon to level 50 minimum. Especially (Future - Salamence), Blaziken and Kyogre.
What do you guys think, is this a good idea? If I should train them, what's the fastest way to do so in Pokemon Sapphire? Lots of Advice will be appreciated since I want a lot of opinions to help me find what suits me the most. Thanks. (:

You should breeze through the Elite Four.

Hoenn is tough to grind in, though Sky Pillar and Trainer Rematches are decent enough.

That looks like a pretty good team, if you ask me! If you're able, would you please give us some detail on what moves you have on your Pokémon? That way, we might be able to help you more.

Why do you have three Dragon types in your team? Two dragons, okay, but three seems a bit much in my opinion. They're also all weak to Dragon and Ice, two types used by the Elite Four. Personally, I'd replace one of them with a Grass type like Ludicolo, or a Steel type.

Kyogre should have no issues trashing the Elite Four on its own. Just run Surf, Ice Beam, Calm Mind, and Thunder (100% accurate in rain). Rain-boosted Surfs cream most of the mons but your coverage options will deal w/ stuff like Walrein, Salamence, etc.

To be honest, the rest doesn't really matter, so I'd use the mons that you think are cool or cute or whatever floats your boat. Because as long as Kyogre isn't criminally undertrained, it's gonna massacre everything.

Also, teaching Gardevoir Thunderbolt is definitely a good idea since its coverage with Psychic is pretty good.