Our website has thousands of pages, and we use Tealium for tag management. Since we have Google Analytics as well, we need to
1. Check all the pages that do NOT have GA. Is there a way to do it in a smart way, instead of checking each page?
2. On some of our pages, we have a redirect to 3rd party vendors, and we lose track of visitors after they are redirected (since we dont have our GA code on vendors' sites). The user is redirected to the 3rd party site where they would complete an action and directed back to our site. Would GA consider it the same session? How do we track the user through GA after they are redirected to the 3rd party site?
Regarding Tealium, it's been a while for me as we've moved to GTM but I thought you could get this from them, no? Also there are services out there like hubscan that will take a look or you can compare GA content reports vs. your server logs.
2. In order to track this completely you would use Cross Domain tracking but it requires your vendors to place specialized GA code on their site:
Lastly, since the users return, you could opt for using the referral exclusion in the property settings:
Best practice would be cross domain -- if possible.