There are two black cast metal legs with levelers on the rear of the bottom of each enclosure, plus the sculpted wood one on the front. Those cannot be easily replicated, though suitable "look-alikes" could be made. Your chances of finding more originals is virtually nil, but you never know until you try.
You'll certainly want to resolve those issues before offering for sale. A Paragon with one corner on stacked phone directories will lack appeal to collectors. I'd put some effort into finding the missing legs immediately. They've got to be somewhere. I don't understand how it's standing without them, but will wait for the pics before speculating further about that.
The clips are simple sheet-metal fabrications, and can be easily made by a local shop.
If the white Lansaloy surrounds are intact, you are fortunate. Don't even think about playing them at this point, for the reasons I outlined above. You won't know their condition for certain until you remove the woofers for inspection and photographing as part of your documentation.
There should be two crossovers on each side. Forget about them. They either work or they don't, and the best answer is build new rather than rebuild or upgrade. If you decide to keep the Paragon, you replace those and store them safely until such time as you do eventually offer it for sale.
I appreciate that it's hard to consider each element in terms of opportunity costs, but look back to my original post here: even after full reconditioning, you may not find the sound to be all that, and anything you do which does not preserve the originality has the consequence of less value in the bank....