How do formations work in multiplayer Divinity: Original Sin?

Question

There's a great general question about multi-player in Divinity: Original Sin. However, as such, the answer(s) are rather general too. My question is more specific: about the formations.

Consider this situation, where me and my friend are playing a multi-player game (in this screenshot I, the secondary player, have just clicked the formation icon top-left):

Note that I am the secondary player, i.e. the third character from the top, controlling the fourth character (an NPC) as a follower.

The formation icons are confusing for three reasons:

• It shows four dots, even though I only control two characters (or do I?);
• The formation setup is displayed linked to the main character (which I do not control);
• My friend controls the main character, and has her own formation choice, which can be different from mine (but also has four dots).

How do formations work, especially in multi-player games!?

Answer 1

Presumably, the "formation" is for the character(s) you're currently controlling, even though the icon seems attached to the first (top left most) character.

Here's an annotated version of the icon:

With this formation, when you issue a move command:

• The character you've selected will go to the spot you clicked on. This will be the 1 dot.
• All linked characters will fill positions 2-4, going from top to bottom on the portrait list.

If you have only 2 characters, only position 1 and 2 will be filled. See for example this move command:

With this result: