XF 1.5 Mass Mail with options

We are working on mass mailing users (something that has been in the works for quite some time and been opted in by users) but with moving to Xenforo we've had some bumps. Now we've got some options but we've lost some as well.

Any assistance is greatly appreciated. Some thoughts that we'd like to see some assistance with is:

How could we...

Set up to send out e-mails using Xenforo based on usergroup.
Set up to move any bounced users to a usergroup.
Set up a test environment where only certain users can get tested (may be directly related to first two points).


Advice on add-ons that might assist us with this.
Users that might be able to assist us (minor or having dealt with this)
Directions that we might have missed as we have checked and rechecked with our server/host for settings and have implemented them as we are using our server for mail server settings. Alternative for mail?

We have set these up (to a minimum):

https://xenforo.com/community/threads/bounced-e-mail-handling.94173/ (looked into this)

This was installed but found to be conflicting/causing issues:


If this is located/created in err, please notify me and allow me to correct.