Have you actually done a conversion onto a real bike? Or are you just assuming it will work? I have no idea what width or axle size they are, or if theres any other issues that would prevent this from working. Personally I wouldn’t trust it.
I have collected 2 Rear wheels with fixed hubs from repco exercycles, basically a 27 inche steel wheel with small holes in a few spots around the rim where they attach small fan blades. Simply remove the fans tension the spokes and seal the holes, or replace the rim if you can be arsed. Absolutley the worst, most dodgyist rear wheel you will ever own. But, didn’t cost anything and matches all those other parts and frame you pulled out of a dumpster. just don’t expect to ride it like you would your more esteemed stallions. why not add a fifth(</>) stead to the stables.
you may also need to change the cog on your new death trap as they often seem to have the smallest possible.