Merging/Joining Algolia indexes and refresh data

Hello.
I have 2 questions in one, so i will break this in two parts.

— Part 1: Merging/Joining Algolia indexes —

In my React project, i’m indexing my Firestore database. In some documents, i have references from another documents. Can i somehow merge multiple indexes?

Now i have something like this:

//people
personID_1 {
name: 'foo',
pet: petID_1
}

//pets
petID_1 {
name: 'rex'
}

And i want this:

personID_1 {
name: 'foo',
pet: 'rex'
}

Note:
Only people names (and another local properties, nothing from another collections) can be filtered, so i don’t need something to search by a pet named Rex or anything like that. I need this merge/join/i don’t know how to name it only for presentation.

— Part 2: Refreshing data —

In this same project, after an user changes some data, i post this data to my Firestore database. I have Cloud Functions to watch this and sync my new/updated/deleted data to my Algolia app. When the Firestore part is complete, i send my user back to my data list, where i have react-instantsearch configured.

Cloud Functions take some time to make the data synchronization, so when my user is sent back and my list is rendered, Algolia doesn’t show the new data, because doesn’t have that synchronized yet. How can i watch for changes in my Algolia app and re-render my list with fresh data?

Thanks in advance.