Any Bosch headlight assembly for a VW will work. Avoid the Chinese crap. I would recommend ordering them from Wolfsburg West (www.wolfsburgwest.com). The parts they have are always good quality, and their web site tells you if they have them in stock.
The big problem with seats in the Puma is that the metal slider assembly that bolts to the floor is very short. Much shorter than any other seats I have seen. If you still have the pair of stock bases, you can bolt another seat to them. Not as hard as it sounds.
I used seats from a Honda Civic in a Volksrod project. The headrests were removed from this car but could stay for a Puma. The seat track mounts were easy to modify to fit the flat floor and they were small enough to work nicely.
The seats I will use in my GTC came from a C series Mercedes.
Further seat info. The Mercedes seats are too wide in the shoulder area for the convertible top mechanism on a GTC. I have now swapped in some seats from a Mazda Miata, They fit well.
The original factory headlights are still installed on my 81 GTC however the shells are rotted and unusable. They are CIBIE "Super Bi-Iodo" headlights with the horse logo in the center of the lens, which according to the markings on the light were manufactured in Brazil