A summary of the changes that you want:
Make Fluffy spawn when 15 or more players are online.
The advantages of this change happening: Well LW has low player count atm, and only occasionally we get 25 or more, some new players who join dont even know about fluffy, 15 is a good number to make fluffy spawn, as it there will be players who can kill with fluffy and also players who can kill the fluffy. All in all it will attract more people as new players will find it something that other servers dont have, and will try and fight for it too!
The disadvantages of this change happening:Noobs being pawned maybe, but if we have 15 players then we surely will have who someone who can destroy the fluffy pretty fast!
Any script snippets which provide the feature that you want: N/A