Currently remote control only supports the primary display. What kind of resolution you using on the multiple screen computer and how many displays you have attached to it?
There will be a page on www.aida64.com where all existing EVEREST owners will be able to convert their existing product key. As soon as it is available we'll push this information everywhere we can.
No, you can keep both softwares on your computer but please make sure you not running them in the same time to avoid possible conflicts in the background.