What is the best team to beat the e4 with my starter being blazikan?

There is no single best team, but create yours based on what you know about them. There are 5 battles. They have favorite types, first is Dark then ghost then ice, dragon and water. It is an absolute must that you have the moves thunderbolt and ice beam. Thunder is also a very useful move. The two Pokemon that helped me the most were starmie with psychic, thunderbolt, ice beam and surf. As well as heracross with reversal, endure, brick break and megahorn. Just make sure you have something to deal super effective hits to each of the types listed above and you shuold be ok, if you bring loads of healing items

There is absolutely no best type because everybody has their own taste. In Ruby, I had Blaziken, but I used a Gardevoir, Blaziken, Ludicolo, Metagross, Slaking and Milotic. I really think it'd be up for your preference.

If you just want me to suggest a few things, then here:

Heracross/Blaziken for Sidney. They will rip through Sidney with Fighting moves.
Dusclops/Banette for Phoebe. They might have a little trouble, but if you use Shadow Ball, it'll be easier.
Heracross/Machamp/Blaziken for Glacia. Again, Fighting moves will rip through.
Salamence/Milotic/Glalie for Drake. Ice moves is all you need. Ice Beam preferably. If you use Salamence, use it with caution because Dragon Claw will hurt you.
Ludicolo/Swellow for Wallace. I really think you should use Ludicolo because Grass moves will rip through the team, and Swellow for the Ludicolo that Wallace uses himself.

For the first guy, I would recomend a fighting type (such as Blaziken, or Machamp), for the second, do not go for an Alakazam, mos of her Pokemon are dark, so you won't do much. Try a sabley, or some other ghost and/or dakr Pokemon. The third one is fairly simple, just use the fighting type you used for the first one, excpet don't use Blaziken, he will get annialated by surf unless he's at a pretty high level. And for the fourth, now he's hard, you want want someone wth ice beam or a dragon type. If you remember when you climbed through meteor flass, were you got dragon claw, you'll find a Bagon, wait till he learns dragon claw and use him. And for the fifth guy, I would recomend a Manecktrike. When I went through, my electrone (manecktrike) was at like lvl 50, and he beat all but two. There you go, hope I helped

1)With Blaziken Have him at least lv.59 for the first 1 (use a fighting move.
2)Use any dark type at least lv.60 mightyena sounds good
3)Have any electric type at least lv 60
4)Basicly any dragon type such as Latios Latias Rayquaza ect. At least lv.65
5)Use any grass type such as sceptile.inbetween lvs.60-75(atleast).

Blaziken: Sky Uppercut, Flamethrower, Overheat, Double Kick (Docile nature)

Shedinja: Shadow Ball, Hyper Beam, Fury Cutter, Screech (Adament nature)

Machamp: Cross Chop, Rock Tomb, Revenge, Strength
(Adament nature)

Salamence: Dragon Claw, Crunch, Fire Blast, Fly
(Hardy nature)

Alakazam: Psychic, Calm Mind, Recover, Shadow Ball
(Modest nature)

Raichu: Thunder, Thunderbolt, Iron Tail, Thunderbolt
(Docile nature)

Sydney: Blaziken, Machamp, Raichu
Pheobe: All
Glacia: Blaziken, Machamp Raichu, Shedinja, Alakazam
Drake: All
Wallace: All except Blaziken

You can do it with two or three Pokemons. Get a rayquaza, yes before confronting the e4. He has outrage but gets soon confused due to it so you can change the Pokemon now (a strong defensive will do ) and change again to the legendary after your defensive Pokemon gets hit. Rayquaza is so fast that most of the time your attacks will be first. One drawback :the legendary Pokemon can't endure ice attacks. The third Pokemon comes into action If you want. Small kids can defeat them using this trick and I have seen it, so easy. Oh yes potions, flutes and revive will be used A bit, after all they are The elite four.