Bicycles wear out tires, tubes go flat, chains wear out. Those are all what are called consumables. Their replacement is normal. Finding a new saddle isn't such a big deal ether. I am not going to be using any saddle that comes from the factory with the bike.

The real question is does the shifters and derailleurs work. A If a little oil or rust busting oil makes the shifters and derailleurs work that would be a good sign. If the seat post can be raised and lowered that is another good sign. If the steering is also not seized.... you've got a nice project.

Take a little time (maybe after the holidays) and carefully clean the bike and oil the moving parts. If it functions.... try new tires, tubes, and new chain. If that doesn't "bring it back" you could always sell it on Craiglist and recoup your parts investment. And have the satisfaction of knowing that a flipper may get it back on the road for somebody.