TOPIC:

The instructions in Membership Management indicate that an email address is preferred, but not required, but when you enter someone new without an email address, a "noemail" email address is automatically generated (and can't be deleted), and "authorization" is required (i.e., the person is shown with strikethrough and cannot be selected from the pull-down menu for assigning roles, for example). I would like to define a generic person - probably in the Guest group - to use as a placeholder for assigning speaking roles to guest speakers who are not members of the club. How can I do this?

You're on the right track.
In this instance the opt-in request goes to your website admin who should accept it (you can resend the opt-in email it if the email was deleted)
Leave the no-email address as it is - it will be ignored when sending out club emails and agendas, although the sender will get a message to say that the email has not been sent to that "member".
Rename the dummy member to something more appropriate , e.g. Guest. If you put curly brackets around the name, {Guest}, it will appear at the bottom of your selection lists

I am the website admin, and diid not receive the opt-in request. I used the "Re-send Opt-ins" and still didn't receive the opt-in request.

Nevermind: somehow, the changes I made yesterday were gone, and I wasn't the website admin anymore. I have restored those changes and now I've received the opt-in request. (Is there some way that changes I make could be "undone" other than by someone else with the admin password intentionally changing them? The floater messages I created yesterday were gone, too.)

Since you have 2 clubs listed in your forum signature and you have not told us which you are talking about, we can only guess which you are referring to. Please be specific when making support requests.

I am guessing that your club shares the admin password. Bottom line, if your club does that, then it is setting itself up for issues. This is why we do not recommend it. We recommend the use of the access settings to allow delegating access to different parts of the admin console to club officers.