Since few releases , its not possible anymore to mix 'Named list' with party names frames .
Also, In the Roles or Group section , you can not uncheck everything (its revert back to fully check)

Working as intended: It has no sense to uncheck everything, this means: display nothing.
I dont understand the namelist issue, party units and player names cannot be mixed in a name list, this thing never worked in that way, the blizzard code used by grid2 does not support this (and never supported this).
Party units can only be used in a custom header (clicking on the "+" tab, to create a new header and selecting "custom" in the header type).

Raid units to be precise. That way you would have multiple same name in one raid group or one name who was not belonging to a specific group in that group.(tank/healer on the far right/left) Unchecking was helping to made some column disappear .

I simply don't understand this issue at all, your are talking about things than never worked/were implemented in Grid2.
There is no version of grid2 (old or new) that allow to mix raid units and player names in namelists.
The same for the posbility to unclick all groups/roles, this behaviour never existed, and is completelly useless because all groups or roles disabled means "display nothing".