I mean I don't know that Mab's particularly concerned with the White Council's opinion at this point, in particular when they did piss-all to help out in the Battle and then voted to boot Harry in spite of what he just did.
In addition, this makes Harry less vulnerable to the White Council's retaliation, because it makes him a key part of an official alliance between the White Court and the Winter Court, meaning that if they decide to axe him for jaywalking like they obviously want to, they have to weigh that against the risks of fighting the White Court (as well as the Winter Court), since he's now become an important part of Lara's power structure.
As far as Lara eating him is concerned, she's probably not to bothered since Lara killing him outright would be a bad move in this case (yeah, just murder a high ranking member of Mab's court under the pretense of an alliance Lara, see what happens) and if Harry lets himself get thralled he probably isn't worth the effort anyway.