Look forward to seeing the finished quilt. The blue will add a 'lift' to the quilt while the brown will probably 'mute' it. Depends on what effect you want but personally, I would like to 'lift' it and go for a bright colour. I would actually use either the blue, yellow, orange or even a red thin border then a thicker brown/blue whichever I'd prefer and finish it off with the earlier border colour that I chose. Then again, it is your creation and you must choose what you like; no matter what, it is still a beautiful quilt. Best wishes.