Alright Xiri, gonna help you there.
Anyway, infernape is an important pokemon to have here.
But why the heck do you have cut in it??? Where did your mach punch go?
In case, you can go to the move relearner in sheridan village if you have a heart scale. But i think it's only one in a day.
The main girl isn't here yet. Also Move deleter in route 3.
Seismitoad - Yes. Typing resistance against poison and eh. Drain punch too.
Tangrowth - Not recommendable for against venam here, but 'maybe'.
Magneton - I don't know this one.
Liepard - Eh maybe for metagross but infernape is here. Also then again, the speed so maybe.
Vileplume - No. Nothing in the movepool works well here.
So now team i picked that is yes for me.
-Infernape
-Seismitoad
Pc pokemon.
Geodude can work for poison resistance and earthquake is always helpful here. However golem isn't exactly here, unless if you want to use your link heart.
Hound doom may fit well too. Nasty plot and flamethrower.
Also sesimitoad can asorb water moves since the team i choose can lack of water moves, but i don't think it's any water moves expect for venam dragalge.
Also i think a flying pokemon can be here and help.
So i reccommend either S. vivillion or S. Jumpluff.
Last pokemon is optional for i can't find the perfect pokemon. You may use the maybe pokemon.
Anyway team current i picked.
-Infernape
-Seismitoad
-Houndoom
-Graveler/Golem
-Shadow jumpluff/vivillion
-Optional
I don't know if this team would work. But it could be tried atleast.