Missions & Complexes

Specifically, 17 of them. That's roughly how many would spawn if you popped both carrier escalations on one of the harder mag sites.

If you theoretically warped 3 or 4 carriers in at once would their tanks be able to handle it? Each carrier would have two local reps and the others would have two remote reps. I'm thinking it would be fine, even for thanatoses without the resist bonus, but if wrong the killmails would be interesting.

You can get 6+6+8+8=28 total battleships in a c5 using 2 dreads and 2 carriers not including the initial spawn. Thats conservatively 400*28 = 11200 dps but really more along the lines of 16000-20000 dps. (I've heard 800 quoted as dps for the battleships)
Assuming you have a boosting command ship in system, using Thanatos' with t2 fits and all level 5's, that means you're going to need a local + 6 reps for 11500 dps tanked, or 10 for 18000 dps tanked. assuming you're running 2 per carrier you'd need 5 carriers to be safe. Though thankfully they rarely focus fire for long, so less could be used as long as you dont mind getting into half armor before they switch off you. If you triage that would be a different story, but watch out, they do neut quite heavily in those numbers. 50 fighters should take them down at a reasonable rate, but I expect only using carrier dps and waiting for fighters to move around you'd be there for at least 45 minutes shooting them all.