A) All of my lighting automations that turn lights on automatically also turn them off automatically. I have a couple (e.g., my dining room, which I walk through far more often than I use and don't care to light if I'm just passing through) that don't automatically turn on with motion but will still automatically turn off after motion stops. Unless my virtual "kill switch" is enabled, all of mine will also turn off automatically after motion stops if turned on for any reason (e.g., manually outside of the location mode conditions that would have warranted them turning on automatically).
B) I only have one motion sensor in most rooms, but I'm thinking about two. Usually I can put one in a good spot as a "turn on" sensor, one that will turn the lights on when active and be in a good location where it won't catch incidental motion from other rooms. I'm thinking of places I can put a second "keep on" sensor I can use to keep lights on but not activate them (something likely to see more motion in the room but might catch it in other rooms from time to time). This might also make "sunlit curtain blowing in the wind" false positives from HSM less likely if used as part of a zone.
C) Most of my lighting automations are driven by a custom app I wrote exactly for my purposes since I couldn't find anything that did what I wanted. I use mostly smart bulbs and have a lot of multi-bulb fixtures controlled by a single switch. I don't always want all bulbs on. I also liked a feature Hue advertised where bulbs would dim before completely turning off as a "warning," then restore their state if motion resumed before then. My app is here: [RELEASE] Lights on Motion Plus (dim before off, remember individual bulb states, etc.). For simple cases, I use the Hubitat stock Motion Lighting app. You can use RM for anything more complicated, but since I wrote my app, I haven't except when I was new to RM to help me learn it.
D) I don't have pets, but I suspect a second sesnor as I mentioned above might help. But I've seen other people use careful placement and even blocking or restricting part of the sensor lens to reduce false alarms from smaller/shorter animals.
E) As I mentioned in the other thread, location mode (and a couple virtual switches) restrict all of my lighting automations. In short, almost turns on by motion when in Night mode, which I activate when I go to bed (or which activates for me late at night just after my usual bedtime in case I fall alseep and forget to do so myself).
There are, of course, no wrong or right answers, just whatever you think works for you. Hopefully you'll get some ideas from this thread! I like seeing what others have done to give me ideas for improvement.