Hi,
The Primary Polling Engine and the SQL are critical to keeping the complex working. Your pics show that the Primary and the Additional Polling Engine are both loaded with things to poll, are collecting metrics and are completing their cycle of polling within their allocated time. From theses pics everything seems to be OK. I wonder if the complex is working fine, but that you don't have the rights to see the metrics from other engines? Are you logged on as admin or are you logged on as another user who may have limitations applied to their account? If you can do a Settings > Manage Accounts > you will be able to see all of the accounts and you may find an "Account Limitation" that restricts that user to only see the metrics from the Primary Polling Engine.
Regards,
Robert