While I do admit that you have some strong pokemon on your team, it is, as mentioned a couple of times already, dragged down by a narrow moveset. Diversity is going to be your main key more often than not. I don't think any pokemon needs three attacks of the same type (granted, there are a few exceptions, but only when they're recommended). I would also recommend trying to use the field to your advantage. There are quite a few moves here that you can use that may help. Just a heads up though, you may need a bit of luck if you decide to do so. If there's something about the field that you're not sure of try looking here to get a refresher. If I remember correctly, there is also someone in Agate that can teach your pokemon bounce and I do believe Blaziken can learn it (... don't take my word for it). She's not Samson, but it can help a bit, since it actually uses the field effects.
... And I do believe that's it. Everyone else has covered everything else I can think of. Good luck.