I currently have a hAP ac2 configured as a HomeAP dual, I need to connect another AP in a adjoining building and am looking for advise on how to configure it, so that it replicates all the setting from the main AP.
IMHO Home-AP Dual mode is actually a mode, suitable for a WLAN-Router, so firewall und internal LAN DHCP-Server is enabed.
I would not advise to copy that config to the new AP, hence.
Using the quick-set for Home-AP Dual on the new AP, but then disable firewall & DHCP-Server, enable bridge on all Interface, etcpp - then manually configure SSIDs/Security/Pwds for both radios is more advisable, I think.
Fairly easy if you understand how it works. (You may lose connection while doing it. Winbox MAC access to the rescue)
On 2nd AP add ALL ethernet ports (and WLAN) to the bridge. (There is no WAN function needed in the 2nd AP.)
On the 2nd AP add or move a DHCP client on the bridge, and remove the DHCP server from the 2nd AP.
Connect the 2nd AP with an ethernet (they are all LAN due to step 1) port to a LAN port of the 1st AP.
Configure the WLAN in the 2 nd AP as you do for the 1st AP.