I'll assume that a couple of people in the Pirate101 community have yet to play Wizard101 (let alone will).
In Wizard101, the major part of the world is kinda based off of 1800-1900 London with a steampunk twist. If you noticed the designs of the mobs have an English Militaritan look. I'd assume, since Pirate101 uses more older styles, the outer parts of Marlybone has a more day time look as apposed to the night sky in Wizard101 and many of the buildings are stuccoed instead of bricked like on the main world of Marleybone. Just look at Port Regal and you can get a general idea of how the clothing and architecture may look when we actually go to the world.
Actually, if it carries over the population of the part of Marleybone you can see via Wizard101, there are dogs, cats, frogs and toads, and rats. In Wizard101 there's also tons of undead and monster spiders running around, but those might be more in the range of "An evil wizard did it!" than actual natives. There were also a handful of clockwork creatures running around that seem to be more or less native, and probably aren't related to the Armada. The dogs may rule Marleybone, but they aren't the only ones living there.