Congratulation on the new home. Also, you are smart to understand that the first step in a good design is having the right furniture arrangement.

The arrangement you drew is a good one. With the counter extended on the kitchen side, I would keep the sofa to around 80" long at the maximum. The chairs should be swivel.

I'd add a counterheight table behind the sofa, but put counterheight chairs under it/not decor. This will give you extra seating. Make sure your sofa is at least 36" high.

Instead of a plant between the sofa and chairs, I'd put an end table

I don't normally recommend tv's over fireplaces, but in this case, it is the only logical location.

I recommend eventually replacing the countertop and removing the overhang portion in the living area only.

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Generally, paint is the last item selected in a makeover project. Color is usually based on the fabrics and textiles in a space. So, the furniture selection comes first. A 3-seat sofa and two chairs is always a good basic plan. Then add casegoods. I really think you might want to put the flooring in first and see how it looks and how it changes the lighting in the space. You're going to need new lights and more of them, and that will effect paint colors too. BTW, gray is on the way out. Take your time and consider some other options.

Ambient (ceiling fixture) task (table and floor lamps) accent (uplights under plants, art lights over pictures) and you'll need a new chandelier 30-35" above the dining table.