Maggie stopped the biting when my husband growled low and deep, spooked her. Took less than a week and we had tried lots of things too. We also left her alone and went to another room, they HATE being excluded. Every time. The climbing and biting has to stop or she will become seriously obnoxious. I have heard it said that every day you live with a border collie you are teaching it whether you realise it or not. They will learn behaviour and continue with anything that gives them what they want, for instance attention.
It sounds like your pup is a bit like mine in that she is bright but wilful. We have seen a real change as Maggie has turned 18 months she has gentled down, some. They can get quite obsessive as they are bred to do one thing, sheep. We know that two walks a day with a lot of ball play is essential and yes they are busy bums.
I do hear you and you are doing fine, they are not the simple to train dogs we are led to believe when reading the literature..lol
I think by nature the kelpie and the collie are one person dogs. Maggie is often walked and fed by my husband and she likes him very much but as she matures it is clear I am primary.Nature I think, in the genes