I think you should be able to monitor lights, plugs and switches in Home Monitor. I recently bought a SwitchBot door sensor that has a motion sensor built into it. I thought that the motion sensor would work directly with SmartThings, but when I got it, it only showed up as a contact sensor. I wanted to use the motion sensor for routines, so I set up a routine on my phone to intercept motion detected notifications from the SwitchBot app and turn on a virtual switch. I recently started using Home Monitor, and I would like to use those motion sensors in it, but I can’t since they aren’t labeled as motion sensors.
do you have a smartthings/Aeotec hub? If so, there are virtual motion sensors you can use for this purpose, it’s the same way people trigger an Alexa routine. But if your smartthings setup is hub free, you don’t have that option. 
Here’s the Alexa faq so you can see how the process works.
No, and I can’t find any hubs under $200.