Use copper rivits for all the wheel riviting and you won't get problems with the casting as you don't need anywhere near the force to form a copper rivit that you would for steel. Aluminium rivits can be used for the strakes if you can find them the right size and don't show up as much as copper on the bare metal strakes.
No hope of buying off the shelf castings, probably easiest to cut from solid, you may be able to find some thick wall tube for the front rims which will save some swarf. A bit small for rolling and welding which is what is done on larger engines. Hubs cut from solid.
I don't think the engine was ever covered in ME.