Voice notification on HomePod Mini?

Anyway to get HomePod Mini to speak a short message?

Yes, but believe you need to subscribe to Apple Music and then code the automations within HomeKit.

Also Hubitat will be doing TTS eventually for Homekit

Has anyone heard any updates on HomeKit TTS?

It has not been announced. It was discussed during the last beta cycle but the dev doing it has had bigger fish to fry at the moment.