Hi.

Is there a way to show the amount of Sleepers and/or TC's currently on the server.

I want to be able to show it in a welcome message

(I am running a new server and players dont stay as they think the server is dead but there are acutually 30 sleepers and 10 bases so itey were able to run a chat command that says the count they my stick around)

You can try 
https://umod.org/plugins/smart-chat-bot
https://umod.org/plugins/info-panel

If you are using info panel it will show sleepers, BUT sleepers can be players that only stay for 20 minutes and then go, there are a lot of players that just move from server to server