OK, I've found against Jumpluff you usually have to drop alot of benched Pokemon to set up and keep up with their speed.
Against any varient the most important thing is keeping out of their 1HKO range, because if you can't you'll probably lose.
Shaymin varients in my opinion are probably an easy matchup, since you can just double Flash Bite and then Dragon Rush the Shaymin Lv X to bring the Jumpluffs down to 90HP. Personally I think that it's difficult to keep up with Jumpluffs if you go down that route and since the deck relies on Sunflora alot to keep bringing out these Stage 2 Pokemon that die easily, I'd try to target them. They're 1HKOs from Dragon Rush, plus if you can keep out of 1HKO range, you can switch between Garchomp C Lv Xs and abuse Healing Breath or Poketurn. Once you can clear the board of the Sunfloras, I'd go straight for the Jumpluffs and after a few KO's you should get them in a position where they struggle to bring one out each turn. Power sprays should help slow their set up as well, on either Uxie or Sunfloras.
Vileplumes gives the deck problems because it's hard to do all of that while dealing with Jumpluffs and having your trainers locked. I think if you're expecting Vileplume, you have to break out of the lock as soon as possible - one turn of trainers can make a big difference. I think the best bet is to get a T2 Luxray Lv X if possible to break out the lock, since they probably won't have a Vileplume set up by that time. If they do, you can usually take out the Oddish/Gloom or 2HKO the Vileplume ( if they have Warp Energy and Vileplume by T2, you’re probably going to be in trouble anyway. ) I think if Vileplumes popular in your area, the best way to beat it is extra Bebe’s Searches.