You didn't have to PM me to ask whether Eruption was good.
Anyway, in answer to your question, Eruption is a good move to have on Typhlosion (especially since his movepool is very small to begin with) but should be used with caution since it very quickly becomes useless as Typhlosion takes damage...which leads me to my next point.
Typhlosion is not a good lead since he'll likely get beaten up by the common leads of this generation, Politoed especially since Drizzle will leave Typhlosion at a horrible disadvantage right away. A sweeper should be coming in near the end of the game, not at the start, unless they have a moveset geared towards stopping other leads, and Typhlosion really doesn't. Either that or have someone else do the straight sweeping instead (you have Volcarona, that'll do.)
Anyway...
- Extrasensory is...well, adequate. The only reason I'd even think of suggesting it on Typhlosion is purely because his movepool is so terrible he hasn't got anything else to choose over it besides Hidden Power, and getting a good Hidden Power type in-game is quite a pain - I can personally attest to that. Otherwise, your moves are OK, but your item and nature are not. Timid is far and away the best nature for Typhlosion to take advantage of his above average Speed stat, and most Typhlosion using Eruption tend to use Choice items, either Choice Scarf to sneak a full-power Eruption in before the opponent can strike back, or Choice Specs to boost its damage by another 50%.
- Volcarona without Quiver Dance? For shame...but if you want some sunlight on your team, a Dream World Ninetales has just the ability you need (Drought) and in a generation where most good teams carry a weather-changer (usually Politoed or Tyranitar) it certainly helps to have your own on-hand. So, yeah, Quiver Dance over Sunny Day, either Fire Blast or Fiery Dance for your Fire-type attack, and again, a good Hidden Power will do wonders over your Psychic attack if you can get it.
- Again, no Dragon Dance on Haxorus, same problem as Volcarona. Poor item as well, nature is OK since Haxorus is already a bit on the slower side of the scale this generation, but consider Jolly if you encounter issues with your Speed being too low. Also, Mold Breaker is the only ability to have for this guy since it lets Haxorus's Earthquake strike levitating Pokemon. Consider Outrage and Taunt as other options, but overall everything bar Dragon Claw on your moveset is useless.
- Defensive EVs, nature and item for Snorlax, and a moveset consisting of nothing but attacking moves - I hope I'm not the only one seeing an issue with this. Curse Snorlax is the best moveset the guy has, combined with some assortment of moves like Body Slam, Crunch, Fire Punch, Rest etc. but overall, you need to make sure your EV spreads, natures and whatever work with your chosen moves.
- Timid is far better than Modest on Gengar due to its frailty, Razor Claw is just no, your EV spread is terrible and your move choices aren't much better. Shadow Ball is the only move you have worth keeping here, and typically Focus Blast, Thunderbolt and to a lesser extent Icy Wind and Hidden Power Fire (both VERY situational) are the only other offensive attacks Gengar should consider. That said, Gengar is quite deadly with Substitute, since it prevents him from being victimized by Sucker Punch and Gengar becomes much more dangerous if the Substitute is allowed to stay alive. Moves like Hypnosis, Will-O-Wisp and Pain Split work well with Gengar's Substitute, but Sub + 3 attacks works nicely as well.
You have space for a sixth person here, but I'll leave that choice in your hands. What I will say is this: Typhlosion and Volcarona both get murdered by entry hazards (Spikes, Stealth Rock) and these will appear almost everywhere if you battle good opponents. Your current team layout is currently very one-dimensional as well (four attackers and Snorlax, who isn't a great defender nowadays) and lacks the basic things most good teams need (aforementioned entry hazards, defense against enemy weather changes) to succeed.
In short, you've got a lot of changes to make to this before it comes close to being good.