Imagine if kae only ever played PvE elements, never joined the forum, and nobody knew who she was, but she was still as skillful. Would it be wrong for serp to include her in his thought processes then?
I do think you need rules to guard against auction avoiding, but it's a case by case basis, and tbh in this case you can't stop people who are in a relationship from sharing their thoughts.
Kae doesn't win anything if light win war.
Kae has no access to other teams vaults or thoughts.
Sure, it's an extra head, but you can't enforce against asking advice, or listening to it, from someone who is physically in the same room, nay, the same house.
If you share an interest with your significant other, you discuss that interest.
Serp is just lucky his significant other is good, my fiancee just calls me a nerd when I ask her about her opinion of brave chrysaora.