Linux
Screen record: kazam
Display picture of own webcam (to be recorded simutaneously): guvcview
Animate mouse movement, show mouse clicks: <nothing reliable found>
Audio Control: pavucontrol
Windows & Mac
Tablet
Linux: App mypaint unlimited canvas >> write without border
iPad: use the internal screen recording function - https://support.apple.com/en-us/HT207935
Android: Screenstream or via HDMI