Two RBR10 bases in AP mode?

I have an RBR10 AC1200 Orbi base unit in AP mode and two RBS10 satellites.  These do a great job covering the office wing of our church.  This WiFi network can be accessed, but is faint in the sanctuary half of the church.  I’d like to extend the mesh to include the entire complex.  There is no LAN connection available in the middle of the complex - only in either wing.

I don’t want to daisy-chain satellites over WiFi from the offices to the sanctuary - I’m afraid that would hurt throughput.  Can I create another AP from the ethernet LAN in the sanctuary wing and “connect” it to the existing mesh?  I don’t believe the RBS10 satellite has an ethernet LAN connector, so couldn’t use another of these as my 2nd AP.  Could I take a second RBR10 base, configure it as an AP like the one in the office wing?  The two base APs can chat via wired LAN.  But would would they play nice and create a cooperative single wide mesh?  Note - neither base is working as router, or DHCP host.  Just working as AP node.