Oh yes! It was important business I had to attend to, and well it's only common courtesy to pay a visit. Merepeople actually and yes they can change form. They use there fish forms mostly for travel ah, underwater. The human form is for land travel. As for the air bubble you'd be surprised how many ship wreck survivors are there! They let people stay for a few weeks, sometimes months to recover. And, well, they knew I was visiting so they might have made accommodations.

As for the-the magic and technology...I can safely say it's definately magic they use. Some water based spells and cloaking spells to keep out of the public eye. But I'm not one for technology so I can't really say.