Dear Rabbi Simon,
Can a weekday minyan meet remotely, eg via Zoom or similar technology, if all the participants can see one another? I suspect the answer is no, but it may be an interesting Q&A subject.
You are right on both counts: They do not comprise a minyan, and it is an interesting Q&A subject!
A minyan cannot be comprised of 9 + 1 on a videoconference. However if there are 10, according to some authorities, a listener may respond to kaddish, kedusha, etc. This is particularly so in a situation such as lockdown (which is currently the case in many Jewish communities around the world), where in-person minyanim are unsafe and illegal (and therefor halakhically objectionable as well). It is doubtful if this is considered as if one had prayed with a minyan, but it would be a close “second best” in extremis. Some hold one can fulfil his or her mitzvah of Havdalah this way, for example. Similarly, participating in a siyum on Erev Pesach. Many were forced/chose to rely on this exigency this past 14 Nissan.
Best wishes and stay healthy
Rabbi Rashi Simon