Having the j bend where the wheels are attached bend further, so wheels start to splay
from folding for parking on them ..
I'd like to have that area gusseted, to prevent that.
the plate that the suspension rubber is bolted to could be good place to start.

A dual shift lever on one side of the bar for the 2 by 3 speed?
twist grip sequence ratios in a linear progression.?

offering a made for Brompton Sturmey 8 speed? 1:1 external sprockets.
[or a modified Alfine 11]
possible to climb most any hill with a 17" 'unicycle' gear..