in uk with blue dog currently and first of all i'd say don't worry - it's easily doable with 5 people with darnnear anything, and dragonite resists pretty much every hidden power it can have so they are decent options always.
the game itself always puts my 2300ish cp venusaur with vw/solar top then my 2500cp confusion/solar exeggutor, after that game usually throws stuff like espeon in as it 'knows' what moves it's facing and prioritises resistances so i'd go with it's suggestions.
as for what moves on an eggy, i'd go psychic quick (think they can only get extrasensory now) and solar charge - seed bomb is a nightmare for attackers if you'll use this on defence after event too.
Already powered up my best jolteon. Raikou is over for me and I already got my 96%. Never got a good zapdos. Best is 89%. I know grass isn't the most optimal attacking type but I want some diversity and also I like using grass types. Always thought they were cool. Beside it's not like they have terrible stays either.
a venusaur is the best grass attacker hands down, vw is faster so more energy and more dodgy than anything an eggy has. eggs are more worth powering up though as they make great defenders with psychic-type quick (iirc on par or tiny bit worse than a supereffective bullet seed so usually the best pick) and solar or seed bomb charge. pretty great neutral attackers too, you won;t regret maxing a high IV one.
as for blue dog counters as we've all said rock a strong lightning or dragonite and they don't last long.
btw i'd not touch any of the other grass types as they suffer from both low cp and (mostly) poison typing. if you catch a good IV lv.30 then evolve away but none are worth dust
I live in a grass biome, so I've long had tons of grass attackers. I still use my eggs and Venusaurs, but my armies of Victreebels and Vileplumes sit unused. My top two eggs have Zen Headbutt/Solar Beam. I never got a good IV with Confusion, sadly. I wouldn't mess with Seed Bomb. For pure grass moves, Venusaur with Vine Whip or Razor Leaf and Solar Beam is the way to go. I also keep one Level 33 Venusaur with Razor Leaf and Sludge Bomb for both attacking and defending.