i'll address the FP, since you seem to need the most help there.

continue the stone all the way up, eliminate the mantle and put the tv on like this

or, go all the way up to the ceiling w/the stone and do your mantle like this one

other options
you could do this trim molding to match the BB, but that mantle you have is too small and too short. wrap it around the sides and make sure it's at least 6" high.

since you are handy, do a mantle like this and build out your shelving/bookcases like so:

shiplap above stone, shelving, lower cabinet. (obviously you only have room for one on each side. the sconces above are a nice touch.

if you look at Ikea hacks, the Billy Bookcases might fit in your spot

another option

Beth, so the last photo you posted is kind of backwards of what the the long term is going in that spot.. The plan is to build out another similar styled "dresser" (not really) with a set of plans I have for a fire wood log holder. It will be of same height, like width, with the wood topper and painted the same colors. This will be to hold logs and also to keep the balance and symmetry.

As far as running the stone all the way up, that isn't something we would like to do at this time as it isn't cost effective for me, as I am not versed in stack stone enough to feel comfortable doing it myself as well as the fact that since the room is already lacking in space by the addition of the fireplace at the last moment, and it requiring so much floor space into the room for fire code, adding the dark stone all the way up will close in the room more and make it too heavy.

I do however completely agree with you on the mantle and paid a LOT of money for a custom slab of wood for the builder to hack it off and not wrap it around. We have another one we purchased to dress the fireplace downstairs as they only left it on a completely bare wall but a similar orientation but only protruding from the wall by 18 inches not 38inches including the hearth.

Thank you so much for all of your in sight and help. I really do appreciate it!

wow! that came out better than expected!!

Put the before picture back up there so people can see it