@asplinteredcell there's a number of things that have me concerned in your post. I'll do my best to address each of them:
1) You mentioned that none of your toons ran with your Tank (Paladin) - this usually means that your other toons are not connected to Dannet. To fix run: /bcaa //plugin dannet load --- once loaded I highly recommend camping each toon to character select and bring them back in. This will take ~ 1minute. The other way of checking and fixing if there is a problem, takes more than 1 minute.
2) You mentioned that your BRD is pulling. That either means that your KA BRD is set to pull or you ran /grind waiver on the BRD and it's acting like the tank. Both of these scenarios are not what you should be doing. I'll address how you should be configuring these classes.
3) Each class must be configured in the UI (/grind ui) - Configuration -> Class configuration. For each class in your group - ensure it's configured correctly.
4) Regarding your Question #2: Lack of Dannet being loaded.
5) Regarding your Question #3: I have absolutely no idea why your bard is pulling unless it's configured to do so in the INI you ran for it.
6) The migration from MQ2 to MQ would not have done any of this wild configuration change. If anything, something would just outright break. The group movement using the Find window is different than before. To move yourself (ctrl + left click) to move your group (ctrl+shift+left click).
If this doesn't help you, please let's talk in Discord and get you fixed up.