when it comes to Vegan vs Thor, in all honesty, Venom could survive a hit from Thor. Negan might be knocked out, however, allowing Venom complete control. Alongside that, Vegan's speed is superior to Thor. so the victor of that fight isn't so clear-cut.
Vader's use of the force could seriously put Thor to misery, though. i know you guys look at Thor as though he's practically unbeatable, but for one, Thor is still weak compared to his comic counterpart, and two, he has no idea what he's up against. he's never faced someone as fast as Vegan, as tough as Bowser, or as powerful as Vader, who's lightsaber would wreck Thor if it wasn't blocked by lightning or Stormbreaker. While Stormbreaker would definitely withstand the saber, the handle will not.
so, in a fight;
Thor beats Bowser easily.
Thor beats Vader while suffering some wounds.
Thor beats Vegan while suffering some wounds.
however, if Bowser, Vader and Vegan double-team and triple-team Thor despite Rocket's frequent distractions, Thor could be relatively easy to take down. he's not taking on an a generic army of disposable troops. he's taking on three characters that could relatively hold their own against him 1v1. 3v1 makes the fight hardly anywhere near Thor's advantage. yes, Thor is powerful. yes, Stormbreaker overtook the infinity stones, but Thor didn't. Vegan's speed is enough to get around Stormbreaker and land some hits, and Vader with the force is good enough to not bother with Stormbreaker and directly attack Thor. Bowser might even get in a hit or two with some pretty powerful punches when Thor is distracted.