>>30800738I did
Timid Nihilego
Jolly and Adamant Buzzwole (Careful would work too if you want bulk)
Modest and Timid Xurkitree
Jolly and Adamant Kartana
I haven't caught Guzzlord yet because I keep getting more Beast Balls. For Pheromosa I would assume Naive/Jolly/Timid depending on the set, for Celesteela there are a few different sets you could run that call for different natures as well.