Your best basic seating options are a 3-seat sofa and two upholstered armchairs. Placement options are pretty much unlimited. For more flexibility when TV watching is the main goal, the chairs should be swivels. You can place TV opposite the FP and float the seating. The window ends will give you space for some casegoods and some occasional chairs. And don't forget art over the mantel and on the four short pieces of the "north" and "south" walls.

Post a photo.

I agree with the others to place TV and attractive wide credenza on the large wall with a great sofa table in the back of floating sofa. Do you need to replace sofa or rug? If not, then a sofa table behind it, with new sofa pillows and two great arm chairs in cream and facing the sofa, and new round coffee table up on legs would give you flexibility for the future. A sectional can be very limiting without adding much seating. You do already have a chaise on current sofa. Etsy offers some great, affordable wood sofa tabletops in any length and height. Just use their search box--"console tables, hairpin legs"

I was thinking that if you put 2 comfortable swivel chairs to the right as you step in (one would be partially at the fireplace), then to the left there would be one continuous curve of sofa to give you the 5/6 other seats you need. In front of that sofa seating put a huge ottoman or table. For lighting, if you can't squeeze a console with enough surface space for lamps, you could probably find a multi-arm floor lamp to put in the far left corner behind the sofa,, and a skinny floor lamp at the window end of the sofa just for reading. I think if you pick the "right" swivel and sofa your husband doesn't have to give up his massage chair, but that means you'd need to be willing to live with bold fat contemporary furniture everywhere, not the usual demure stuff. Shock of the new, and it might be way too much in the contet of your whole house. Whatever you do I think you should consider at the end whether an area rug with very dark tones in it helps make your sunken living room more of a choice than an irritating mistake.