BG172151115 Thereare 2 versions. One version (2A) which takes the switched power only from the RX (So no additional electrical connection is needed between the control (the RX) and switching contact), and the 2nd version (20A) that will switch the power from an external source, based on the RX signal. This version has the extra (3rd) lead. Hope this helps.

BG172151115 Thevideo streaming is via a mobile app (V380 Pro, which is one of the better generic apps). Once you have set up the app with the camera, you'll be able to stream to your mobile from any remote location so long as you have an internet connection. I have not tried multiple access, but this should work so long as you set up each device individually. But please note, the video quality is only average on these cameras - they are small so it is a compromise, and across the internet you get some lag and slow fps, but this is to be expected.

BG172151115 Yes - it's a Canon 700D in the sample pictures.

BG172151115 Sorry,I don't know as this is designed for Ender-3.

BG172151115 Ifthe parts of your extruder are plastic - yes!