The art your ordered would stand out nicely on the fireplace against the dark brick. I know you said you had another mirror in the space but how about doing something like antique mirror tiles with glass shelves behind the bar. There are tutorials online that show you how to antique mirrors.

I think continuing with the gallery wall would be fantastic, but the pieces look a little wobbly at the moment. I think the problem might be that they are not straight. It might also be that you are trying to put vertical and horizontal pieces together in the same size frame as the horizontal pieces. I think you need some larger pieces in the mix. I use glue dots on the corners to keep the frames straight. The smaller the frame, the more noticeable it will be if they are not straight. If you keep what you currently have, I would rearrange so that the vertical pieces are not all in the same row. @idaclaire has a fabulous gallery wall in her bathroom!

This is a duplicate post. can you keep everything to just one of them? https://www.houzz.com/discussions/6031063/help-i-need-ideas-on-how-to-finish-decorating-my-living-room#26272579

Do you have a sink light? If not add one. It makes a huge difference in function and mood lighting. I just added a wall sconce above my sink and it makes me very happy.