How is this for a preliminary network diagram?

Hi everyone, I am working on a network diagram to bring Wi-Fi to a remote office in the mountains. I am working on a budget, and would like to get this as close to right as possible right from the start.

Data usage: 1TB per month, for non-critical remote work, for about fifteen people.

Site notes: We plan to use a Starlink as the primary internet connection. There is no fiber or cable access nearby. LTE is only available 200m away on a hill near the upper building—that point has line of sight to a cell tower ten miles away. 25 Mbps over LTE is consistent.

Burying conduit will not be a possibility before early summer.

Distances: Hill <-200m-> Upper office building <-300m-> Lower office building

Hill: there is AC power here. I will have a Pepwave LTE router here, with an ATT 100GB /mo data-only SIM. Planning to use a Nanobeam to send data to the upper building.

Upper office building: Multi-WAN router connected to Starlink and Pepwave LTE connection, using Starlink as primary, failing over to LTE if Starlink goes down. One PoE nanobeam pointing up the hill, another pointing down toward the lower building.

Wifi: We have been using Eero Pros but I am open to suggestions.

Lower office building: PoE Nanobeam aimed at upper office. Nanobeam connection plugged into switch switch connected to a Wi-Fi setup similar to that of the upper building.

Here is the preliminary diagram: https://imgur.com/a/ApzAvvF

My main questions:

1. How can I choose the appropriate Ubiquity wireless bridges? Are they easy to set up and reliable? Do they come back online automatically after a power outage?

2. Besides Eero, what is a good Prosumer or inexpensive professional Wi-Fi solution? We can wire everything with ethernet cables.

3. Are there inexpensive Multi-WAN routers which can gracefully failover to the backup internet connection, then test the main connection every minute or so and switch back over when it is back up? I imagine this will mess up the public-facing IP of all of our users—however, I am not sure we need to aggregate the links, so maybe an occasional failover and jumbling of IP addresses isn't so horrible.

Any advice much appreciated! thank you.