Congratulations on getting there and this on your own. I wonder about the situation with the chain on the lowest cog. How far is the tensioner arm then from the ground? Can you fold then fine without the chain getting loose or do you need to watch on which cog you need to fold? With the bottom bracket, was that that the chainline was off? Did you try asymmetric placement of the bracket, different amounts of sticking out to the left than right? What is the cassette you ended up using? Thanks.