Rick,
Thanks for the compliment on the website work. It is a work in progress.
Below are my answers to your questions, but I would add the disclaimer that I am not claiming to know all the answers – just giving you what little I know. : )
Exif data is usually stored with each image – even if you don’t do any special settings. This information goes along with the image from the camera to the processing program (iPhoto, Lightroom, Photoshop, Essentials, etc.) and can be accessed in different places. Since I have never used Essentials, I don’t know where to tell you to look for it, but check the “view” etc. in the menu bar and see if any say anything like Exif or photo information.
http://exifdata.com/
This is a link to a website that will allow you to upload an image and see the data that is available. Just click on it, chose a file (like one of the ones you posted here) and click upload. It is surprising what information is stored there. (If you want to quickly do this, just click and hold on your first image, drag it to the desktop, and then upload that image. Depending where you have your images stored this might be easier that finding the original image.)
Normally I try to focus on the eye that is closest to the camera since it is the one that is first noticed. If it is a straight shot (without one eye or the other being closer) either will work. Remember, the lower the f/number you are using the less that there will be in focus. Normally on portrait type shots you want the subject in focus and some blur in the background to call attention to the subject. I found an app called Field Tools that shows the depth of field for different cameras and lens. I don’t use it all the time, but it is sometimes interesting to see how small the depth of field is with a lens.
I set my camera to read one (usually the center) spot for focusing. I do this since I am usually having it focus on one item: person’s eye, spot in a landscape, etc. Sometimes, seldom but sometimes, if I am going to be shooting landscapes I will change that to pick up additional areas. Usually I will just look at the f/stop setting and will have an idea about how much will be in focus and still use the spot focusing.
When I got my 50D I bought the Canon EOS 50D Digital Field Guide by Charlotte K. Lowrie and it has quite a bit of information in it. She also has one for the 40D that is listed on Amazon. http://www.amazon.com …Field-Guide/dp/0470260440
You can get an inside peek at some of the pages to see if it looks like something that would help of if it is not needed. There should be some used ones if you start looking.