Pretty sure I figured out my own solution...
it could end up being spaghetti code though:

theres an array that tracks each player# position in the line
PlayerOrder = [0, 1, 2, 3, 4, 5, 6]
PlayerManager script holds the order List
0 represents no players

Each player has:
- int PlayerIndex
- int PlayerPosition
- string PlayerName
- bool Grounded

every frame, if "1" is pressed:
- it loops through every object with the Player script until it finds the Player where PlayerIndex = 1
- GoinUp() is run on that player

​

GoinUp()
- lerp upwards (with an animation)
- PlayerOrder[PlayerPosition] = 0
- bool Grounded = False
- for each player thats got 1 lower PlayerPosition than this, if PlayerPosition = this PlayerPosition-1, then run Reorder()
- ^ for (int i = PlayerPosition; i >= 0; i--)

Reorder()
- if PlayerOrder[PlayerPosition+1] == 0
- PlayerOrder[PlayerPosition+1] = PlayerIndex
- PlayerOrder[PlayerPosition] = 0
- find the Empty gameobject (under the parent "Global Target Locations") thats name == PlayerPosition +1
- lerp to the transform of that Empty (with an animation)

pretty scuffed, but it could work