It's actually riskier with a custom recovery since it's not officially supported by the root solution developer(magisk in this case)
Not fully, without affecting stability Stock roms may not play well with microG signature spoofing :P
I'm running a bacon right now!I'll soon upgrade to an oxygen(mi max 2) when mi unlock allows me to :(
I mentioned this before but I'm not seeing any arm only(arm32) apks