Avahi, multiwan and more

[SpaceBass]

Hey folks,
I have just added a third remote site using OVPN. So far, so good on the tunnel itself.
For the sake of this post, I'm talking about sites A and B only, leaving C out of the mix for now.
On both ends of tunnel A-B, I have created interfaces for the tunnel. Traffic is passing fine.

I have avahi enabled on both ends with nothing but "local" (sans quotes) in the domain field.

Question1 - that's not working. Is there anything specific I need to do? I've seen some dated posts which suggest "it just works", however that's never been the case for me, at least not with tun.

Also, site B is a multiwan setup, one pipe is a dedicated business line pipe. The other is the local municipal wifi…hey, why not use it? I have configured multiwan just fine and even have some complex routing rules to make sure outbound business traffic stays on the business pipe.

Question 2 - how can I make sure the OVPN connection from site B to site A always uses the business gateway? In other words, where do I create that rule? LAN, WAN_biz, elsewhere?

Thanks in advance for any expertise and guidance!