to create a group you may just need to create individual units and group them together separately.
Wrong. ;D Sorry.
Every unit is a member of a group. (Unless it is dead.) Automatically. A unit that is not a member of a group is an impossibility. If you have a unit, you have a group.
You can't createUnit a loon except into a pre-existing group.
If you place a unit in the editor you are by definition creating a group, although you can immediately destroy that group by putting the unit into another group.
AFAIK there is no command to create a group. The only way to create a group is to place units (including gamelogics) in the mission editor.
The command
group returns the group of which the object is a member. It has nothing to do with group creation.
Returning to the original question, there are certainly dead body deletion scripts in the Ed Depot and I suspect respawning scripts too.