The frame geometry in the first photo bothers me a little; is it possibly bent?

I cannot assess the rust damage from photos. But since you're attached to the bike, I'd try to save it. Can you visit the bike in person, or have a good mechanic inspect it and determine if the frame and fork are straight and sound, before it gets shipped? If so, I'm sure you can have it sand blasted and painted in Poland, upgrade a part or two, and you'll have a great bike. But note, I said "if." That's the important part.