Whoever you should decide to go with, understand that nobody makes 100% of the products that they sale. The point being that you may be thinking your purchasing one brand when in fact, it is another brand.
When it comes to seat covers and door panels, SMS tends to be the only viable provider for the earlier cars. But expect to pay dearly and I hope that your not in no hurry for them. Legendary may possibly be making the 65 Satellite seat covers and door panels now for that car. I would have to check. Legendary is running a special now and will probably be having specials going on through the Holiday season. But I know that the independent vendors for the Legendary brand can almost always beat the manufactures pricing. Again, for that particular car, I would say that your looking at six to twelve weeks on product delivery. No matter who you go with, test fit immediately upon product delivery.
For carpet, you only have one alternative. That would be ACC Carpets. All of the vendors sell it, so you just have to search out the best price and your preferred vendor. For carpet, seat covers and headliners; I do not believe in ordering them until your to the point of installing them. It takes a bit of planning, but you do not want the components all folded up in boxes for months or years awaiting installation. If nothing else, remove from the box and lay out in a suitable place if available.
Also take into consideration the shipping on these pieces. Based on your location, the shipping for some vendors may impact the final pricing that you pay.