It's good of you to offer qualified support on products you don't sell (if you did, I would ask you for a quote).
My understanding of your #1 is that it can't be any old switch, or even any Hikvision switch. They sell a couple of dedicated switches - or "
video/audio distributors" as they call them - within their video intercom range and assured me I needed to get one of these specifically. I'm about to find out.
Your #2 makes sense since Hikvision tell me that local mobile devices connect to an indoor station (monitor) only and not to the door station. I didn't ask why but assume it might be done this way to preserve the core functionality of the intercom unit even if multiple mobile devices are trying to access the system at the same time.
I would like to hear from anyone who has Hikvision's 2nd gen video intercom installed and functioning nicely across mobile devices.