Can an agent host a Brokers Open House while a property is in "Coming Soon" status on MLS?

My answer is no. Showings are not allowed during the Coming Soon status. An open house for cooperating brokers could be construed as a showing. For agents who advertise their listing on their Facebook page or in a Facebook Group for agents, the home must be listed in the MLS within 24 hours in the Coming Soon status. It has been marketed outside the listing brokerage, and the "public" includes cooperating brokerages. I see agents post all the time, and then other agents tell them to send them the details. This violates the MLS rules if the listing is not in the Coming Soon status.

How do you determine how many homes were built in a subdivision?

Another option to try first is to explore neighborhoods through the HAR homepage. Sometimes the number of homes is mentioned. Otherwise, I agree with the above and use Realist.