Ok, first of all, Cambria is a good shop. Just give the bike a good look over to make sure they didn't "trade out" components. I have heard some stuff about one of their shops. Don't know if it's true, but always good to be cautious...

Now as for buying a component online and then asking them to install it?? Ohh that made me bristle. It's kind of like taking your own food into a restaurant and sitting at their table and eating it. It just seems to be bad form IMO. There was a discussion amongst lbs owners in a trade mag about that recently. Some say they will, some say absolutely not. It's hard to exist as a brick and mortar with the internet folks under cutting you. BUT if they are not able to get the component you need, then I would say it's ok. Have you asked them if they can get it for you, and if so what kind of price they'll give you?
I know some shops will install for free if you purchase it from them. For our shop it just depends. I would think that most shops would be willing to work with you tho.
And NO, I do not think you are evil for buying online. When I'm pricing things for the shop I always try to look at what the online market is pricing it at. I can't always match it, but I try to stay within a stones throw.
One thing I don't think alot of people realize either is that some online stuff is previous years goods. So they think the lbs is overcharging them for say a 105 rear derailleur, but what they lbs is selling them is a current model, and the online version is 07 or older. If your lucky your lbs will have an older model on hand and is prolly discounting it.
As for the fit. Does this shop have a certified fitter on staff and charge for it? If so, then no worries. That's part of their business model. It's just another service, so I wouldn't think twice.

I had a similar experience a couple of weeks ago. A lady came in and asked me to measure her for a bike. I took all her measurements and plunked them into the system. Gave her the size, saddle height, reach, etc. and then she took those measurements to my competition. Apparently she had a credit at the other store, so she was going to use it to order a road bike. She didn't like how the other lbs had measured her, so she came to me. Sure enough, He had measured her big. Which I attribute to the fact that he can't get the bike smaller than a 48cm. She measures at a 45-46. The bike she's getting will be too big for her. I'm sure I'll see it in here when it doesn't fit. I'm not certified yet (coming after Ironman) so I don't charge anything. And I also don't put it out there that I will do a professional fit. But I do know enough to be able to swap out stems, adjust cleats, etc.
I'm just hoping that by helping her it will eventually mean she'll actually spend some $$ at my store, rather than just use me for my knowledge. All I can do is hope. At this point I'm trying to spin it as good bike karma...

Hope this helps. You are not evil!! No worries!