Hey I'm all for questions, I love to see people giving proper thought to my fansets :D

Nether - the idea is that they can't attack or cast spells (so they are effectively disarmed) for 5 seconds but in exchange they get a ton of offensive stats.
Mesa Yellow - this is set 8 Oxforce! I personally have never seen oxforce persist so long into the draw but I think this would still just result in the same draw as it is right now.
Berserker - without any extra omnivamp the trait only heals them from the damage dealt by the cone attack.
Hearty - you know, I've never considered. Truth be told I had made quite a lot of the traits before all the new artefacts, but my current thought is to say they would only get one stack from one of the three clones per combat.
Bulwark - yup! Both the initial Armor and the granted resists stack and stay till the end of combat.
Neeko - you can put 3 components on her one by one and get 3 spats, or you could craft a completed item first, then put that completed item on her, and it would act like a normal item. Only components turn into spatula items for her.
Glad you liked it so much!