Newby needs advice with strange T related project

[nosoup4u]

I'm primarily a John Deere collector and have decided to embark on a project of building a John Deere Speedster using a combination of Deere and model T parts. I've got a small Deere flat head engine and am planning to use a radiator from and early Deere tractor that has the cast iron top tank with "John Deere" cast in it. It is roughly the same size as a T radiator. I have an old T frame that spent much of its life under a wagon box. I have some questions which I'm hoping someone might help me with.

The rear end has had its guts taken out. What other rear end might be a suitable replacement in terms of size and easy of installation? I wouldn't mind of it has hydraulic brakes.

I believe this frame was fairly early but don't know how to tell for sure. It had wood spokes but the centers have been bolted to 16" disk wheels. Where can I find complete T wood spoke wheels at the best price?

Would I be better off converting to 21" "A" wheels which I can find fairly reasonably on ebay?