Ask at fabric stores for names. Or maybe try decorators. You want somebody who does good work unless you want a loose, really casual look. I found a woman who does impeccable work and she charges about $400 for a sofa with multiple cushions. You will need a lot of fabric, so consider that part of the cost as well. Definitely worth it if your alternative is replacing a higher end sofa with something current - new will either cost much more now or be much lesser quality. Excellent USA made furniture is either crazy expensive and/or hard to find IMHO.

Sounds like a wingback. I had an ivory wingback chair that one of my cats shredded to death, for lack of a better description. I think it's in their stretch, and I know as crazy as that sounds, my cats never claw my slipper chairs, and they're much shorter , so low sides, lower back. Buy a Matlasee coverlet and tuck it in where needed to fit the chair or have a slipcover made from one. The chair sounds like an odd size but Calico Corners could probably make you a great slip, but it will not be cheap.

I like my natural colored slipcovers. Yes some one can spill bbq sauce, but what if they spilled on your dining chair? Unless you are using all wood or vinyl, it is going to stain. Being able to take it right off and treat the stain with out damaging the frame of the chair is a nice thing. Personally, I would look for a less expensive version, but that is due to my wallet, I would probably love these if I could afford them. You can find other covers so you can switch out if you get tired of the white. Since I am busy sewing my own slip covers right now, yes they can wrinkle and shrink. But taking them out of the dryer while still fairly damp can make it easier to stretch them to put on. I have an older and much loved couch that has had the covers washed a lot with no issues with the seams. I did replace the seat cover because over time (and with the help of the dog) was not coming as clean as I would like

I‘d start with the slipcover, as they are not easy to find regarding decent fabric quality, size and shape. Suggest blue, white or green and add cushions that complement drapes. I‘d skip a brown rug and wait until you decide on color scheme. Consider your taste/comfort with mixing patterns; see above. Use a textured rug to make it easier to coordinate around and if your preference is a solid.