Lets see. Keep Earthquake handy. That alone can probably take out Typhlosion, Infernape, and Luxray with one hit each. There's really no need for 3 fire types on your team, so balance it out with a few other pokemon. Venusaur has a ton of weaknesses. Try wiping out his other pokemon, then go for a clean sweep on the rest. that lugia is going to give you the most trouble. Use super effective physical moves, as he has lower defense. I would teach something to take car of him to your ho-oh. Sacred fire is physical and can do quite a bit of damage. If your friend uses lots of stat boosters, then punishment would be the perfect move, since its power is based on stat boosters. Venusaur can go down quickly due to its low speed if you trap it. Feraligatr can't do much defensively, so he can also be quick. The trick is to put different type moves on pokemon. You can give thunderpunch to one of your fire pokemon, tricking him into sending out Feraligatr, and taking a quick kill.
So in short:
Luxray-Earthquake. one hit will take it down with its frail defense.
Lugia-Use physical super effective moves with ho-oh.
Venusaur-Sacred fire would be an easy kill.