It doesnt have to be full happiness for Oak to accept it. That you traded it is also not the issue as I traded multiple starters for the quest and never had a problem doing so.
Dont know what else could be wrong here though.
Already has been suggested a couple times. I think the repel price should stay as its a good money sink but Max repel should be adjusted so it has the same cost per step as super repel.
Little off-topic but I was wanted to let you know that Suzuka Cave from your suggestion on that thread is just an exclusive area from the easter map 2020.