This is informative:
"Can Meetings be Conducted using a Videoconference Service?" and the answer is yes, provided that the remote participant can hear what's going on at the meeting and be heard by those actually present at the meeting location.
We have used Apple's FaceTime for a few years for board meetings. One of our directors is a seasonal resident and he connects to another on-site director's Apple device so we can see and hear him and he can hear us. Theoretically he can see us also but constantly shifting the local device around to aim its camera isn't perfect. But as long as he can hear and be heard, that's fine. A remote director could even participate over a speakerphone setup.
I don't like getting locked into Apple's ecosystem - Facetime does not play well with others (like Skype) - but as long as we have people on both ends with Apple devices we're good. Another potential problem we're facing in a few months is there is a second director who wants to also participate in meetings remotely. That might be a problem with a 3-way videoconference and what we use now isn't going to work.
Sorry, but I haven't really looked into what services are available. I know it can be done because I've watched videos where multiple participants at different locations all take part in the procedings.