The S1H is just fantastic but... even though I consider myself something of a minimalist, in order for me to do what I need to do, I use on every job:
Stills camera (S1R)
A cam video (now S5, was S1H)
B cam video (S1H, was S5)
Each of the above has a principle lens and an alternative lens based on circumstances.
Back up and BTS cameras (ZV1 and Action 2)
Drone
3 tripods, 1 monopod, 3 lightstands, 4 lights, 6 pieces of audio capture gear.
You know those, "what's in my camera bag?" videos, well I have 4 bags ๐คช
Sounds a lot but only at certain times am I using most of it at once such as during wedding speeches, I will have my 2 principal cameras on me, roving, (as I do all day anyway, ie, I never take them off other than to eat) while the B cam, back up, BTS, lights, off camera flash etc, are all tripod or light stand mounted and set up during quieter moments.
I draw the line at flying the drone while attempting anything else though as I'm paranoid about crashing it into a tree. Or a granny. As I have done several times. (Trees, not grannies).
The S1R is a big enough beast and having the S1H on my other strap for anything from 9-15+ hours is just that bit too much and the S5 is just a lot easier to handhold all day with cage and additional grip.
The principle I believe with one area is yes, you generally 'point' that in the direction of your subject and if it's a face, it should switch to face tracking/pick it up and track as such.
I need to give it some more time as I've only just switched to it from 'normal' face detect only, but in some back to back tests, it does seem better.
I'm not sure what Quick AF is. Or I've forgotten. It's not a stills thing is it...?