How can I find out if this tour company is legit?

[MineralMan]

4. I'd be a little skeptical. However,

You can set up your own Beatles tour with a well-established tour company in Liverpool, and just arrange your own transportation and lodging through an airline that includes hotel bookings. Here's a website for such a company in Liverpool. You might save a bundle.

http://www.beatles-tours.com/index.html

The site you linked to has a facebook page, too, but very few actual reviews from people who have taken the tour. Their graphics capabilities on their website are pretty awful, as well. I wouldn't book such a trip without a long conversation with the tour operator.

Anyhow, you have other options you can follow that might be as good or better, and you could combine some other interesting activities on your own.