Chrysler fabrics had a metallic tint to them and the vinyls had a pearl tine to them, even white vinyl. You don't realize that until you put a non-Chrysler fabric/vinyl against the factory items.
Legendary might have the front bucket seat foam, if needed, as it's the same for Chryslers, Dodges, and Plymouth C-body cars back then. Getting ready-made kits in OEM fabrics might be a trick. Look in the Legendary catalog, even online, and see if you can find something similar in seat configuration and body series. IF you find something similar to what you have, you might contact Legendary to see if they can use those basic patterns and build something with OEM fabric/vinyl for you.
The deal with upholstery is that you have to get it pulled tight on the foam/seat base build-up to get rid of wrinkles and loose spots. Not quite like hemming a cuff on Dockers or jeans.
Getting the correct machinery to sew everything together is important, as it having a large work table to lay everything out on, mark the patterns, and other seams. Quite a bit of labor involved in doing these things! Not to mention experience in how to use the machines and such. Not to say that somebody who hasn't done it before can't do it, but just be aware of how much time and labor CAN be involved. If there is a community college with an upholstery course you can take, taking it might be a good thing to do BEFORE you venture off into your possible project.
As for a local upholstery shop? Check with new car dealers and see where they might get their warranty upholstery work done. Used car lots, respectfully, usually just want something "covered" and little else, which is much less than what's expected by a new car customer who desires the repairs to be "as factory".
The upholstery shops who have done dealership work will have fabric/vinyl catalogs for the OEM fabrics and can probably order them for you. Probably from their supply network which might end up being from SMS, by the time it's over. BUT they would know how much to order, to start with, which can be important.
Might some of the slip covers at Walmart (or similar) work?
CBODY67