Just a simple zscript mod for GZDOOM that implements the MBF helper dogs like they were in their origin port. Player starts 2-8 will be replaced with a custom actor that spawns a helper dog depending on your helper dog setup. It also has support for chex quest, heretic, hacx, and partial support for hexen & strife.
You can choose how many dogs spawn in a new options menu that's in: Options > Gameplay Options > Cooperative Settings > Helper Dog Setup
By default only one dog will spawn and it will spawn on the player 2 start but it can be tweaked to use all 7 non-player 1 player starts.