Extend Party Limit (via ScriptExtender)

What you need:
Download and install Norbytes  BG3 Script Extender (with Console)
(it's important to use the version with console!)

How to make it work:
- Launch the game and a console window should show up in the background
- Start a new game (or load a save) and switch to the console window
- Type or copy the following commands into the console (without quoations):"osi" - "Osi.PROC_CheckPartyFull()" - "SetMaxPartySizeOverride(x)"
(replace the "x" with the number the party size you would - i just tested till 10, but more should work also)
- switch back to the game and invite the companion(s) to your party
- go back to the console and set back the party size to 4 with "SetMaxPartySizeOverride(4)"
- Play the game with more than 4 charakters in the party ;)

If you want to add another member later, just repeat the console steps.