I'm very new to running multiple displays, and currently trying to find my preferred setup. I think my ideal scenario would be the following:

As a general rule, I want for applications to open on the display the mouse cursor was on when they were opened; if I open them on my secondary display, I want them to open on my secondary display, and vice versa. However, I'd like to be able to create exceptions for this rule. For example, I'd like Spotify and Discord to always open on my secondary display, also when they're clicked from my primary display.

I want my secondary display to be where desktop notifications show up. Generally, I want my secondary display to go into a lockscreen and/or fade when my cursor isn't on it, and automatically go back out of the lockscreen/light back up when I move my cursor back on it, or light up when I receive a desktop notification so I can read it. I'm essentially imagining it functioning similarly to a phone or tablet automatically "locking" or "going idle" when I move my cursor away, and automatically "unlocking" when I move it back or receive a notification.
However, I'd also want some kind of toggle to prevent my secondary display from going into a lockscreen or fading, so when I'm playing a game on my primary display, I can still have Discord or a browser tab showing on my secondary display. I hope that makes sense.

I also want my secondary display to have an auto-hiding taskbar with a minimal kind of layout, but I want the windows and pins to mimic my primary taskbar, so if I for example have a Firefox window open on my primary display and then click it on the taskbar on my secondary display, it will automatically move it from my primary display to my secondary display, automatically resizing to fit, and vice versa if I then click it on my primary taskbar. By default, it'll just minimize/maximize the window on the display it's on, no matter which taskbar I'm clicking. Just as with the application launch behavior, I'd like to be able to create exceptions for this rule; I'd like Spotify and Discord to retain the default behavior.

I apologize for the lengthy text. Thank you if you read this far. Does it sound like the above is something that would be attainable with DisplayFusion?

Thank you, I'll try my hand at triggers even if they're a little difficult to wrap my head around. As for number 3, is there no way to work around it with windows profiles, functions and triggers? Or could you create a Jump List shortcut for it somehow?