As for the Dreamworks IP's, none of them are anchors at this point IMO. 5 years ago Shrek was. Madagascar, KFP, and HTTYD never were huge. Decent midrange IP's, but not anything you tie anything more than a ride to, and all are on their way downhill or past their prime. Trolls is an interesting case as it's got huge merch numbers, I just can't get behind it as an anchor. That might be just personal preference though. But even if you combine all of the Dreamworks IP's into a land, its just a hodgepodge and not an anchor. They aren't going to make any of them as a park weenie. Mario on the other hand can give them that. In USF, Mario will always play second fiddle to Potter.
Universal doesn't need every land to be an anchor. They just need one or two characters that they can use in advertising and lesser characters to fill out the park. Harry Potter and Nintendo are those anchors right now. DreamWorks just fills out the roster.
That said, when Nintendo was first announced, it was definitely going into KidZone. Then the internet exploded. Universal suddenly realized they had a potential Harry Potter II on their hands, which forced them to take deeper looks into their options. The KidZone area was clearly too small to handle the Nintendo land everyone was clamoring for. Maybe they could put Mario Kart into the Toon Lagoon theater area and then retheme the water rides (Donkey Kong is such an obvious fit for the rapids ride!), allowing the land to open much faster! Maybe they could retheme Lost Continent! Maybe it should be saved for the new park! OMG OMG OMG!
Then reality reared its ugly head. USJ was getting their version first and space is limited over there. OF COURSE the US parks would be getting clones. So Universal has decided upon the obvious fix of plopping a Nintendo land into every park, a la Harry Potter. First, they had to go through the planning process and figure out what configuration would fit in all three locations. Orlando still had issues, as the USJ configuration could still fit into the Toon Lagoon theater area, and IOA needs Nintendo far worse than USF does. Toon Lagoon has long been Universal's most problematic area, and Universal finally had a major fix. Or certainly a better fix than the Secret Life of Pets/Illumination retheme that was the most recent rumor.
Then Comcast bought DreamWorks Animation. Suddenly the Toon Lagoon options exploded. DWA is certainly not Nintendo, not Harry Potter, not the Minions. But its characters are definitely closer to those in stature than Dudley Do-Right or Popeye! Furthermore, DWA's Fab Four are still spitting out sequels with a new Shrek and a new How to Train Your Dragon coming soon, a new Puss in Boots and a new Madagascar in development, and a rumored 4th Kung Fu Panda being written (not to mention sequels for second-tier films Trolls, The Croods, and Boss Baby on the way). Those characters will sell way more merch than Beetle Bailey!
So KidZone will get the clone, IOA will probably get Zelda (in Lost Continent) and the new park will probably get Pokemon (if they also got that IP) or all the remaining Nintendo characters. (I've long found it suspicious that USJ's land will be called Super Nintendo World. Super Nintendo brings up images of a long defunct game system. In the world of Nintendo, the word "Super" has long been associated with Mario - Super Mario Bros, Super Mario Land, Super Mario World, Super Mario Galaxy, Super Mario Sunshine. Nintendo's two biggest releases of the last year continue this Super Mario trend: Super Mario Run and Super Mario Odyssey. Considering this land doesn't stray outside the Mario canon, the choice of adding the word "Super" to "Nintendo World" is an odd choice. Yes, Nintendo World is the name of their store, but wouldn't "Nintendo Universe" fit better in a Universal park? Which leads me to believe that USF's version will be Super Nintendo World up until they need that name for a different land, which is when USF's land will become the more appropriate Super Mario World.)
What’s the anchor for Epcot,AK, and DHS?
Disney doesn't need anchors. Disney's anchor is the Disney brand. Disney could build half-day parks and people would still show up in droves. Because that's exactly what they did (at least in Orlando).
Universal, on the other hand, DOES need anchors. Just look at UO attendance pre-Potter and post-Potter. IOA was arguably a better park than any WDW park, with anchors - Jurassic Park, Marvel, Dr Seuss - that are way more popular than most of Disney's output. They had world-class coasters, world-class water rides and the world's best dark ride. Yet it took a boy wizard with a history of mediocre books and movies behind him to turn that park into a competitor.
Strangely enough, Disney is now learning that it MAY actually need anchors. Pandora is an outside IP brought in solely to compete with Harry Potter. Epcot is now getting a Marvel infusion to go with its questionable Frozen injection. The Studios is upping its Star Wars and Pixar content. (MK will still rely on the Disney name though.) Each anchorless park - though I would argue that Spaceship Earth has always been a major anchor for Epcot - will become a park anchored by a major IP.