Automating the recording of pet feeding using HA with GA integration

Here’s my use case;

I want to be able to record, query, and issue reminders according to if/when my pets have been fed.
e.g.

Registering new pets:

User: “Ok Google, add a pet to my household”.
GA: “Ok, what’s the Pet’s name?”
User: “Scooby”
GA: “Ok, and how many times per day is {pet_name} fed?”
User: “4”
GA: “Ok, when is {pet_name}'s {n}th feeding time?”
etc etc etc.

  • sqllite table to store the pets’ feeding times.

Recording feeding events:

“Ok Google, {pet_name …} has been fed”

  • sqllite table to record feeding events.

Querying if pets have been fed:

“Ok Google, has {pet_name} had his {meal_identifier}?”
“Ok Google, have the pets been fed?”

Automatic issuing of reminders if a pet has missed a meal:

  • timer triggered script to check whether each pet has received sufficient feeding events prior to their feeding time, issuing a reminder to all Google accounts linked to the GA.

I don’t want to have to say “Ok Google, talk to {agent}” prior to issuing these commands.
By my understanding that means Google’s conversational stuff is out the window.

GA Routines don’t support parameters, so I can’t have GA Routines that invoke HA-exposed scripts.

So how do I go about implementing this?

Virtual devices exposed through HA to the GA, which implement custom actions?

My current understanding is that HA only exposes a predefined set of actions to GA, so how would I go about exposing additional virtual devices that have custom actions defined?

gbridge.io-like GA to MQTT translator?
It’s currently unclear to me how the GA-side of this was implemented, and how it’d be applicable to HA.

I’m a professional programmer, so don’t mind getting down-and-dirty at a code level.
However at the moment the whole HA/GA ecosystem is rather alien to me, so I need some guidance on where to focus my efforts.
(p.s. I’ve already setup GA integration with HA; that was the simple part…)