There's no risk. They talked to Nabisco, said, "Hey we wanna call the next OS 'Oreo', coo?" And Nabisco said, "Ok."

Maybe money was paid one way or the other. Or not.

What restrictions are you imagining?

Even with negotiations, If a engineer said in a Google youtube talk "Oreo is Americas favorite android," they could set themselves up for trademark infringement.

If Google had a line in a blog post that said, "It's better than real Oreos", they could likely be sued.

Oreo would not like Google saying either of these things. So Oreo needed to make up legal documents to map out all the things Google is allowed to say about Oreo Android. It seems like an unnecessary legal headache - one for dubious marketing gain.

Licensing a trademark means not having to worry about such fine-grained details. There's no reason anybody would have a problem with "Oreo is Americas favorite android" What is there to sue over? The damn thing is called "Oreo"

Same with your other example. That line is clearly humor, and keeps the cookie brand's name in people's minds.

I think you're overthinking all of this.