Auto Comment Poster/Expirator/Reposter

Any suggestions on how to accomplish the following...

I am running an autowebinar with specifically timed queues
towards the end of the webinar for "pre-asked" general
questions I'd like to program into the comments area.

Actual live attendee will see these comments appear as if
they are just posted from other attendees (avatar too). I
want the ability to have these comments appear at minutes
29, 31, 35... and then 90 minutes after the event, to have
the comments "disabled" and reset back to appear again
tomorrow at the same time.

Any suggestions will help.