If I had to, a sturmey archer X-RD (free wheel threaded, no internal gears) would play nicer with the flange adapters(same thing as the clamshell)
I like the idea of a moped rear drum brake better though.
https://www.treatland.tv/complete-peugeot-103-rear-36h-hub-assembly-p/peugeot-rear-hub-4492.htm
Has sealed bearings, mounting points built into the hub and a threading for a free wheel. Would lace up into any spoked rim with 36 holes. Uses these sprockets (cut for 415 chain) but any machinist could make a sprocket with the right pitch and tooth width for the chain you want
these sprockets have a 94mm ID and 11 mounting holes with 16mm offset. they will fit many peugeot 103 rims and motobecane rims. the hole pattern is the same as puch, but puch uses a 12mm offset.
www.treatland.tv