For the speaker, I think I'd look at a couple of options. One is to recone, possibly retaining the stock voice coil and former as well as the stock field coil. If the windings are good, maybe a competent speaker repair shop can replace just the cone and glue the new one to the existing voice coil former.

Another option is to look watch eBay auctions for old tube radios that aren't in good condition and that are selling for $10.00 or $15.00. You'll find lots of radios like this there. Write to the seller and ask the condition, size and configuration of the speaker. Some sellers may not take the time to look at the speaker, but many will. If the back of the radio is open - as it is in many cases - then one can easily look at the speaker and measure it with a hand ruler. If you find one that has a field coil and measures the same size, you may have something to work with. You might buy it and take the chance that it can be used; You'll get other spare parts this way too, and might be able to find the pushbuttons.

It's sort of like a "grab bag" trying to find replacement parts, if you know what I mean. Finding a speaker that has the exact mounts that you need might be difficult, and sometimes the field coils aren't quite the same. But my experience is that the field coils and supply circuits in these table radios are pretty forgiving in this regard.

Lots of these radios have no back panels; Seems common for them to be missing. But I have replaced backpanels with fiberboard having holes for hangers. It is a very common material that you'll find in almost every builders supply store. I see it a lot in garages and storage rooms, where the holes are used to mount hangers that hold yard tools and what-not. You can buy this in sheets for just a couple dollars, and cut it down to the size you need.

I bought a sheet of about 4 square feet and had the builders supply cut it down to sections of 8" x 12", for radio sized backpanels. Cut it to fit the radio, and then cut any holes needed for AC and antenna wires. Sometimes, the loop antenna is fastened with screws or glued on. At any rate, once the panel is fabricated, and mounted, it looks appropriate and the holes allow ventillation for tubes.