No picture of your room. And that's a honking BIG sectional, and will not be flexible at all. You'd be better off with a sofa and chairs unless your room is huge.

We really can’t understand your question. “Would it be ok in front of the shelf?” What shelf? And we can’t see any entry door so we don’t know where it is or if a couch in front of it is a bad idea. The way the room is arranged now, IMO the sectional is way too close to the fireplace/tv. How do you watch tv now? Lying down? What are the dimensions of the room? Typically you need a very large room for a sectional to function well. Is that a pathway that needs to remain open behind the couch? We can’t tell.

Yes, I would say just start looking at the different companies (they all have websites) listed above and you may find sectionals available within a couple of inches of your desired specs, which would certainly be less expensive, depending on the brand, than having one custom made. I love sectionals and just bought one from Macy’s during their Black Friday sale which was the right size I needed and didn’t break the bank. I had obsessed over the size since our living room is pretty small. Size is important, but not just length . If space is limited, then width, height, and general “bulkiness” are also important. I was considering a higher end, super comfy brand called Lovesac but it was just too big/bulky for my space. So, instead of spending 5000, I spent just a couple of thousand at Macy’s. The other fun thing you can do with a modular sectional is add to it, pretty easily! For example, I may swap out one of my end pieces for a chaise, in a couple of years. Don’t know if this is as easy to do with a custom made…. Good luck!

What do you currently own and choose to sit on? Do you like to lay down while watching TV? Do you want to have your feet up? How many people normally sit in the room? How many when you have guests? Do you want to cuddle with someone? Do you have difficulty getting up from a seated position? Do you do sewing, crafts or puzzles while watching TV? Choosing furniture that is going to function well for the way you live requires knowledge about how you will use the room and your personal preferences. Size also matters. My mom was 5'2" and my dad was 6'4". They never liked the same seating. Recliners are probably the most frowned upon option per designers, but many people love the comfort. Some also need to put their feet up. Many don't like a chaise lounge, but my sister and her husband have a sofa with a chaise and use it every day - her laying across the sofa and him on the chaise. They have 2 chairs but choose the chaise sofa. I love my sectional, but that is what works for me in my space. Only you can define this.