Re: rear suspension
Have you hooked up the final drive chain yet? I think you might have a major problem on your hands with the chain slack.
With that geometry you might have slack that approaches or even exceeds 1" - maybe slack of two or more chain links. A regular tensioner can only take up slack of less than two links and who knows about the tensioner travel.
The reason bicycles and motorcycles can get away with it is because the pivot point is almost exactly in line between the front and rear sprocket centers, thereby keeping slack to a max amount of around 3/32". And since this bicycle was designed to be driven by the bottom bracket, it would satisfy this requirement for proper chain slack.
I don't always listen to Alice in Chains..... but when I do, SO DO THE NEIGHBORS