Sorry for the delay in replying.
Before I answer your questions, I’d like to share the way I usually test out notifications on staging sites with several production email addresses and not spam everyone.
Basically, all you need to do is to change every email address to a “plus alias” address that you have access to in gmail or hotmail or any other service that accepts them. Plus aliases are basically aliases to your own mailbox. Taking ‘[email protected]’ as an example, you can do ‘foo+whatev[email protected]’ and get 2 addresses for the price of one :).
On staging sites, in order to get unique addresses for my own mailbox, I run the following query (having wp_ as example prefix):
alter table wp_users add column orig_email text; -- create a new column to back up the original email addresses update wp_users set orig_email = user_email; -- back up the original email addresses update wp_users set user_email = CONCAT('foo+', user_nicename, '@gmail.com); -- Create the unique plus alias address for each user pointing to your chosen mailbox
Then you don’t have to worry about spamming the actual users, as you’ll be receiving all emails in your selected mailbox.
Now on to answering your questions…
Q1) Can I assume the following lines:
[2023-02-22 11:49:46]  [bbpnns_memberpress_bridge]: Dropping blocked user ID102
[2023-02-22 11:49:46]  [bbpnns_memberpress_bridge]: Dropping blocked user ID104
….is the bNPSS Memberpress bridge doing it’s job and preventing the email being sent to the two test pilots registered so far?
Correct Memberpress is telling the bridge that each user cannot access that forum and the bridge is correctly dropping them.
Q2) If I assign the test pilots to only the ‘Subscriber Test Pilot’ role after they register and make them the recipients only in bbNPSS, is this a way to allow test pilots on staging play with the forum without any emails being sent to regular members?
Please use the technique I outlined above so that you don’t have to worry about not sending out emails in complex user access situations.
Q3) When I push/deploy the staging site back to live I should then update bbPNNS to have recipients as Participant / Moderator / Keymaster? Do you agree?
Because you’re using Memberpress (or any other supported membership plugin), setting role-based notifications is recommended. That way, bbpnns will load every member for the given role and the bridge will weed out the ones that do not have access.
Q4) relates to what these test pilots see in their front-end account profile subscriptions page. Will the subscriptions (Forums/Topics/Replies) listed here depend on the config of bbPNNS at the time they registered or can it be dynamically changed by subsequently altering the settings of bbPNNS ? The reason I ask is that of the two test pilots i have registered so far, they have completely different subscriptions listed (see attached) and I’m wondering if this was because bbPNNS was configured differently between the registrations.
It may very well be. In your screencast, I see that you have the option to automatically subscribe all new users to all forums. That is why they were registered to forums that they weren’t allowed access to. I recommend that you disable that and keep the role-based notifications enabled. Or, if you haven’t installed it yet, have a look at https://memberpress.com/addons/bbpress/. They may have an option to automatically subscribe new users to whatever forums the group is allowed.
Let me know if you still have any questions.