4th Gen Help with sinnoh elite 4.

[GabWright97]

I'm onto E4 (1st time playing Platinum or Gen 4 as a whole this year) and i'm stuck at 'em for a while also after so many defeats.

Nick (A male Infernape level 55)
Moveset: (Rock Climb, Calm Mind, Flamethrower, Close Combat)
Matt (A male Bibarel level 54)
Moveset: (Surf, Waterfall, Curse, Rock Smash) (Yeah sorry, had to make someone on my team an HM Slave otherwise i wouldn't advance in-game, xD)
William (A male Staraptor level 55)
Moveset: (Fly, Defog, Aerial Ace, Brave Bird)
Natalie (A female Luxray level 53)
Moveset: (Crunch, Flash, Thunderbolt, Thunder Fang)
Cedric (A Bronzong level 52)
Moveset: (Psychic, Flash Cannon, Earthquake, Faint Attack)
Grinch (A male Abomasnow level 50)
Moveset: (Strength, Blizzard, Rock Slide, Grass Knot)

I hold on my own pretty well against Aaron, but Bertha and Flint are pretty tough even with my type coverage, had to use lots of Revives and Full Restores on my team just to reach Lucian, lol.

 

[Nah]

Since you've made it to the Pokemon League you don't really have to keep all those HMs in your party (keep Fly though). Bibarel at least can be swapped out for another Pokemon. Maybe some other Water type with a good Water move and Ice move. Or Metal Burst Bastiodon, I liked that one a lot the last time I played Platinum. There's possibly multiple options you could go with.

 

[Corveone]

Replace the HM moves with something more useful, and reconsider your movesets. Staraptor doesn't need three Flying type attacks, not when it's missing great moves like Close Combat, Return, and U-Turn.

Train some more. What are you expecting from an Abomasnow at only level 50? That's not only around 10 levels below Cynthia, it's literally below all of the Elite Four aces. Get everyone to at least around level 58, you shouldn't be underlevelled unless you have a really good plan.

Consider strategies depending on the Abilities your Pokémon have. If Luxray has Intimidate, it can lower opponents' Attack while baiting Earthquakes, then switch to Staraptor which is immune to it and also gives you another free Intimidate. If Bronzong has Levitate it can also help against Bertha, while if it has Heatproof it may help against Flint. If Bibarel has Simple, it could setup against some physical attackers with Curse, especially if Staraptor or Luxray intimidated the opponent first, it also has access to Yawn to put opponents to sleep.

 

[Devalue]

One cheaper strategy: X items. Accomplishes a lot with just one 50% boost (but preferably more). Recommends doing it against a physical Pokemon after an Intimidate or two. Applies to things like Bibarel's Curse too. (Would say Infernape's Calm Mind as well, if not for the huge amount of Psychic attacks throughout the Elite Four. Doubts much advantage to powering up versus Flint with just Flamethrower on your side. Probably only helps versus Aaron.)