Is it possible to add a console command?

removebuild {steamid} - to remove all buildings of the player (cupboard owner)

runescape

and what if said player built parts of a base that belong to another, or multiple players?

I understand it. But this is the admin server command, the admin will already decide how to use it.

tomhud

removing all player entities works a treat but does it really have to kick the player in question ?
TomHud kicked: From RemoverTool Plugin

Can it not work on Player Name as well as SteamID ??

either way,good job Arainrr

Kicking the player out is necessary because it will remove the player himself.
Please check this thread: 
Names are not recommended as they may have the same name.