With the Thanos script mod properly installed, in GTA 5 Scripts folder you will find a folder called "Thanos script files", and inside this folder you will find a folder called "Suits":
Inside the folder "Suits" we have one .ini file for each ped model that appears on Thanos menu:
Then you open this new .ini file with Notepad (run notepad as administrator) and edit the variable "name" to set the name you want to be displayed in the menu item and edit the variable "model" to set the ped model name you installed before:
Save the file, load the game and now a new item should appear in the mod menu :)
The other mods uses similar idea, what changes is the folder where the .ini files are located (some are in "Characters" folder, others in "Armors" folder) and the .ini file name pattern (some have _armor, super_suit_, char_, etc.).