Also you asked for the most stable so I gave you the most stable. If your question would have been 'which are the stable version' probably my answer would have involved that image too.

where have you configured the DHCP server? Do you have two configuration settings of DHCP on your network. Is internal DHCP also configured.

why do you want to set it to workgroup bridge , why not root - non-root setup. It would still function the same way.

4.2.130.0

yes ap can be used as a scaner though I would still prefer Airopeek as a sniffer.