I have had various 2cv's over the past 18 years. Can't claim to be an expert, but the 'modern' front disc brake ones do use LHM. I'm not sure about the older drum brake versions. The rear drums on both are the same.
In general the front brakes worked really well, they were overengineered, designed to stop the GSA with a 1300cc engine as opposed to the 2Cvs 602cc. The rear brakes on the other hand hardly worked at all. I think the front took all the force. On the car its quite difficult to get them apart. Simple parts which seemed to sieze easily, you need to hold the drum still while undoing a big nut 32mm If I remember correctly.
I guess you could get the whole swingarm assembly and weld that under your chair ! The lomax is a 2cv based 3 wheeler. It can use the same chassis, the rear swingarm is modified so it can hold the rear wheel centrally.
I am biased but all petrol cars should be 2cvs. 60mpg is normal, the emissions are actually lower than from supposed modern cars with catalytic converters. The engine is a flat twin that just goes on and on. Its the nearest you can get to a bike in a car. Though with the standard motor top speed is generally legal.