hi! maybe these will help
Diner seat, like a booth seat? if so, You’ll need to take it apart and find where the vinyl was stapled and remove the staples.
Foam is better than batting, but requires a more surgical approach.
The seat can be removed - usually 4 screws into seat base. Remove staples holding on old fabric and use the old fabric as a template for new fabric. Staple new at center of front, stretch fabric and staple at the back center. Repeat for the 2 sides. Continue stapling around perimeter by alternating locations to keep fabric tight. Return the seat to the chair and fasten with the screws.
Without seeing what the chair looks like now, it is hard to offer suggestions on what you might do to improve its looks. Please post a picture.
The cushions are pretty easy to remove. If you turn the chair over and remove the screws, the cushions should come off. Recover them using new fabric and reattach using a staple gun. You will have a brand new cushion!
hometalk has some ideas:
Re-upholstering is one of my favorite things to do to update furniture. You will have to remove the fabric. Please check out my blog post https://karupp-did.net/fabric-removal/. This will give you an idea how to remove the fabric yourself. I explain all of that in the post how to label it and keep the pieces organized if it were a bigger project(like the bench I did in that post). Also what tools you will need to get all the tacks out is all in there. When you remove the old fabric then you can get to the refinishing of the wood on the chairs if that is what you are planning to do. Then check out https://karupp-did.net/bench-part-3/. I did a 3 post series on how to re-upholster. For your application, just check out those 2 posts. This post will show you techniques how to staple it all back up. I am assuming the cushions are good and you will only be replacing the fabric. Is there any fabric piping involved on the edges of the cushions. If you are not experienced with sewing, you can just forego the piping and just re-upholster it without it. Are the seats curved at all. If so, check out my post....https://karupp-did.net/re-upholster-with-white/. This post goes into detail how to re-upholster around a curve! Good luck!! I hope this helps!