Edge 540 workout and brightness features i may be missing

Hi

I've owned my edge 540 for over a year now but honest answer is I barely use it compared to my other bike computer (out of respect for forum intent I wont mention as this isn't intended to be a complaining post). I've searched the internet/manual/forums etc but didn't really get any answers to the following or that it wasn't possible. 

This computer was my attempt to return to garmin as i liked the form factor of the edge relative to it's screen size and battery life. I was a owner of the edge 500 a long time ago and was very fond of that little computer. 

Hoping for some guidance on the following from other users who are likely quite well versed in the edge series and it's ecosystem with garmin connect. 

1- Interval training / workout overall graph view as part of graphical output 

Is there a way to see a whole workout and my point in that workout session as a graphical output? 

I know i can select the top right button and then click my way through it to see it when doing a workout but would like to see it live as a graphical output with the workout data (i.e. power, hr etc) when doing indoor interval training on a preprogramed workout.

2 - Workout intensity adjustment +/- from 100% of target output

On Zwift (and my main bike computer), i'm able to do this on the fly but on the edge 540, this feature is entirely missing (or not easy to find). Some days i'll adjust the intesity either up or down depending on how i feel (i.e. coming back from illness or feeling great that day etc).

How do you do this or mimic this feature?

at best i think i could adjust my FTP setting up or down pre workout on the phone and then let it sync,, but i'd prefer just to do on the device on the fly. 

3- Auto brightness on the fly

Does the edge actually do auto brightness? as in if i'm riding and i go in a tunnel can it automatically turn on the backlight when it senses it's gotten quite dark or does it not have a light sensor?

I suspect that it's auto brightness is clock based on sunset/sunrise... 

4 - Map Navigation Fields

Currently i can only see that i can have only 2 data fields max when running the navigation/map mode. Is it possible to extend to 3 or 4?

I'm guessing no, but thought it'd throw this out there in event someone has worked out how.

Honestly, I really want to like the edge 540 and would like to make it my go to computer but the workout features and brightness items above are holding me back. 

Cheers