Are you able to stack another viv on top of the existing one? Most people do it that way - a real space saver but there's also all the equipment to buy.
At the end of the day it's up to you what you do, considering rehoming shows that you obviously care for their welfare
it's a shame that your friend couldn't keep them but you're obviously trying to do what's best by them.
The thing about any animal is that they can seem fine one day and the next they can be fighting, anything and nothing can set it off. Also it's not just physical fighting that's the problem; in reptiles body language, eye contact, colour etc can be used to intimidate each other. This can really stress them out and cause ill health. If they aren't fighting then it buys you a bit of time until you can decide what to do. There's tonnes of threads about cohabiting beardies so have a look at these; housing males and females together continuously usually ends in the female becoming ill or injured and you ending up with a lot of eggs (or vet bills).
If you can get a picture of where the probe is that's best, then people can suggest if it needs a little tweak. I would leave the bulb until you can get digital thermometers so you know what action to take as the thermostat dial is useless when it comes to temperatures.
Electrical side of things, you can unplug the heat mat. It's not needed. That just leaves you with 2 plugs. If you have an extension cable you can put both the UV and the thermostat on a timer so they have a proper day/night cycle (and then you don't have to remember to do it).