Is it possible to add a cooldown to fmini, it is a really nice feature, but being able to constantly spam minis to get back to fights is a bit OP.

I added this feature and submitted a PR for Spooks to review on GitHub, which you can see at the following link.
https://github.com/Spookywooky3/SpawnMini/pull/14

You can download that version now from the following link, but keep in mind that the version that is released may be different if there's any feedback from Spooks:
https://raw.githubusercontent.com/WheteThunger/SpawnMini/master/SpawnMini.cs