I suspect there’s a reason for this absence in the Google Family Library is related to the functionality of part of Plus. Since I don’t have any experience with this Google Family thing, I can only speculate that this Google package allows sharing of the same resources.
One of the Features of Plus is that it gives you individualized confirmations of reception of Group messages. This might be a good thing for many families, allowing you to know everyone is on the same page. Not sure how that would work if you were sharing it out of the same file.
In fact, with the need for different user accounts to really make it usable on separate goTenna Meshes, I’m not sure how shared resources would work in general with GTM. Does Google have any comparable sorts of apps or devices that are paired with the phones of a family group that suggests this is even technically possible?
If it’s any consolation, not everyone necessarily needs Plus to take advantage of many of its features. For instance, if you know you’ll need offline maps, get them on a couple of the devices (however many needed when your family breaks down into smaller groups at, say, an amusement park or zoo) and that may take of your needs.
IIRC, the enhanced six hops you get with Plus allows the recipient of one of these messages who only has the standard 3 hops to respond to it and it will be handled like the six hop original…if I’m wrong about that someone will let us know.
Thus two of the most desirable features of Plus can still help in a group environment with workarounds that would seem to serve OK without everyone having Plus.