Can watchers get notifications when I post a comment on my listing?

No they won't.

Hi Owen to my knowledge the only way a watcher can be alerted to a comment or question being added to your listing is if they are using BidBud and have a bid amount scheduled for that listing then they can select the option to have BidBud email them if a comment or question is added to that listing. See the screenshot below from BidBud.

However SJ, according to Andrew, as I asked him this a year ago, "It will only email if a comment or question is asked if you place a bid, or monitor the auction." Simply having it on your watchlist with no other interaction will not get you any notifications.

Hi Gary yes that is correct as I said in my post you must have a bid amount scheduled on the listing for the email questions/comments option to work with BidBud.