I would not use a designer on staff at a furniture store. They may or may not have credentials, but they for sure will be glorified furniture salesmen and you're liable to end up with a furniture showroom in your house. What I would do is go through the millions of pictures on Houzz and the internet for inspiration, save them into your empty ideabooks--one ideabook for each room--and then go shopping for pieces to complete your favorite look. The other thing I would do with a blank slate like this is not to buy a single thing till I had everything planned out. I'd put all seating, case goods, rugs, art, curtains on a mood board and keep switching them out till everything looked good together. Room wasn't built in a day and no one ever died from sitting on this for a few weeks.

Based on what I see- there's a large hard surface to the left and right. So I would put a soft textured fabric, possibly patterned fabric headboard, simple rectangle shape like one of these, except low profile (something that sits behind your pillows and doesn't go much higher.) I wouldn't put anything above it since there's a lot going on on that wall. Just some nice bedding and a couple throw pillows. Just my personal opinion, not a pro!

I feel option A is better among all, except for the play area because you will be having a whole room downstairs for that. And maybe move the dining a little to the left near the window. You can add a partition to divide the room into living and dining and mount tv on it. Place a storage unit /crockery unit behind the partition. I would still recommend you to opt for the layout shown in the 3d renders as its quiet functional and space is best-made use of. Maybe instead of a tv on the wall, you can use a media partition to divide the living and the dining. The wall along the kitchen can be used to place storage units or shelving. Let me know if you need me to do more 3D layout to help you visualize better.

Since you have it on the opposite wall, I wouldn’t do another whole wall in it. I would like a shorter backsplash like idea two, but....I would extend the shelf all the way across to each end. Then, I might stagger a series shelves rather than have just two across.