It's a mythological thing. Greek, I think. Salamanders (the creature) were thought to be able to live in fire or even to generate fire. The salamander heaters are usually long tubular things, often set on a stand horizontally. Maybe the heater was supposed to physically resemble the creature? For whatever reason, they've been called salamanders for a long time.

Would you like to try a couple of different arrangements? One is to put the big chair back where it was, then place the two recliners together at the end of the room. Put the end tables on either side of the sofa like you had them. Then find a table to put between the two recliners. You can try them angled toward each other a bit or just have them lined up straight at a 90 with the sofa. Between the fireplace next to the recliner, I would probably have a big basket with magazines, or throws and pillows. A tall plant in the corner by the window would be great. Second, take the big chair out of the equation and place the recliners across from the sofa on either side of the fireplace. I would put them on a 45ish degree facing inward. Each should have a small table to use for drinks/lamp/whatever you'd like to put there. This will leave the end wall completely open, but I think it will be easier to imagine different pieces of furniture/art there. Definitely get your furniture placed in a way that makes you think "ahhhh, this is perfect". THEN we can worry about the art and accessories. I was surprised to see two recliners. Didn't you only have one before?

I've had a hard time trying to define my style as well - when we started the planning process for our house - all I knew was that I wanted it to architecturally be as craftsman-style as my budget would allow. That drove some big decisions like cabinetry style and interior doors - trying to keep all the big stuff going back to the craftsman style. In terms of the little stuff like light fixtures, drawer pulls, color schemes (dark vs light and warm vs cool) it took me a long time to figure out my style doesn't fit into one bucket. (So we call it transitional!) My best suggestion is to take your time. Start with photos, walking through decorated model homes, walking through furniture and décor stores. Take photos of everything you like. Then look at them. A lot. If you're like me, something that you LOVED initially and snapped a photo of, 3 months later you're over it. I found that to be a good way to sift through the trends to find what I REALLY love. if I had started purchasing items for our to-be-finished home two years ago, I'd have an HGTV modern farmhouse... because I saw it SO much I thought I loved it. Turns out, I don't really like the whole farmhouse, rustic style. It just took me time to marinate on different ideas. Good luck! (Not sure if this ramble is helpful at all, I tried.)

Get a better stud finder. Zircon makes several decent models in the $20-30 range; they have a standard and a "deep stud" setting, which can be useful for plaster walls. I just used one to mount a heavy oak stair railing in a house with plaster walls. The stud spacing I encountered was 16" in most locations, but varied, and sometimes there were double studs; I would have missed a number of studs if I counted on consistent spacing. Once I located a stud, I put a piece of masking tape in the location and marked what appeared to be the edges. Later, after I had them all marked, I used a 1/16" bit to drill several tiny holes at each location to make sure there was actually a stud there and where the center was. If your brackets don't cover the little holes, it's a trivial matter to spackle them.