Welcome, my name is XXXXX XXXXX I will do my best to help you with your issue.There really isn't a cost effective product to clean up the old doors. You could use Formby's furniture re-finisher but it's kind of pricey for this application. I'd just wash the old doors with TSP if they're grimy then sand lightly and give them a coat of polyurethane. Matching the new doors will be trial and error. Get a small piece of luan plywood then do some test strips with various stains (Minwax is a good option) and poly to see what will match most closely. Or you can use Minwax Polyshades which is a one step stain and finish product.
Hi Rick, I applied the methods you suggested and used Minwax with stain. Just didn't like the results. If I were to paint the doors, what products and steps would I need to apply to ensure the paint doesn't peel? Thanks for your most expert advice. :-)