1999 Trooper. Brake lights flicker, front turn signals flicker, and dash lights dim when brake applied. What is it?

NOTE: all problems listed started at the same time.

Problems:
Noise is constantly coming from shifter and brake lights flicker.....
Happens when: Ignition is in ON position, running or not running, brake not pressed, in
park, and most importantly when headlight switch is on.
Doesn't happen when: Headlights are off, brake is physically pressed

Front turn signal lights flash on and off.............
Happens when: Car is in drive being driven, headlights off, turn lights off
Doesn't happen when: Head lights are turned on.

All dash lights and clock,  dim, brighten, dim, brighten when brake pressed.......
Happens when: Headlights are turned off, brake pressed.
Doesn't happen when: Headlights are on.

At highway speed the rpm's rev up and down as if it won't go into next gear....


To my knowledge the possibilities for all
Alternator is going bad
Needs battery (even though it is new)
Bad ground somewhere
Possibly brake light switch (but for all problems?)
Shift linkage sensor/relay etc (for all problems?)
Needs new wiring throughout.

I haven't gotten the battery or alternator tested yet, was hoping before I do so someone
might have an idea before I go all in.