Any advice on:
a. Configuring the Network Manager to recognize the bonded NICs so I can use it to connect to my VPN provider or,
this is simply out of scope of this forum since network manager of each distro has nothing to do with openvpn itself.
b. Connecting to my VPN provider without using the Network Manager,
you can try something like
openvpn --config configfile
or you can start openvpn as a service.
Michael.