I have handled the Sony and it is not all that small. My Olympus OMD M1 is very similar in size, and with my very large hands is totally comfortable. I have been using it for 5 years now.
One thing I noticed when I pulled out my old film Canon AT-1 was that most digital cameras have much larger bodies than my old film camera! Even the Olympus ones! Try one at a camera store as suggested by others and see what you think.

To question 1, it is the number of pixels on the sensor period that determines resolution (given that you are using good glass - that also affects the res).

2. The manufacture determines the number of pixels on a sensor. 24 mp is 24 mp. You won't get more resolution on a bigger sensor, just better light gathering performance (less noise). I had this question when I was looking at whether or not to move up to a D700 or not.

3. A little confusing on the crop, but try this. Place a print on the table (or on your screen- whatever works) and view it. Then cut a rectangle in a large piece of paper and place it over the picture you are viewing. You have now cropped it. If you think of the photo as a full frame sensor, and the window as the
effect of using a cropped lens on your ff camera, then the number of pixels in that crop is the number of pixels as calculated in area (square whatever of opening X pixels per square whatever). Same for a crop sensor when you zoom in. But if you compare a photo taken with a ff camera and the photo from a crop sensor camera, using equivalent lenses, they will both look the same (might be some slight variations, but not worth racking your brain for) - I compared a D700 to a 4/3 camera this way, taking same photo with each, and no discernible difference.

Hope this helps a little - difficult subject to either question or explain!

That is why I don't stay on the "bleeding edge" of technology changes and instead am a "fast follower" (some terms I picked up during my time in the corporate world).

I was offered a free Epson large printer (don't remember the model number) but when I researched it, the ink cartridges required to run it would have cost several hundred dollars. Then there was paper to buy and we were not sure if the printer even worked! It also must be used regularly to prevent clogging of jets.
As someone else commented - LAB!

I have one on one of my cameras. It does get in the way of the access ports, but they are usable in landscape mode. Unfortunately, my port is on the left side of the camera, where the L is formed, so I cannot use the ports for remote triggering when in portrait mode.

It is a very nice feature to have, but I mostly keep the camera horizontal on a tripod, so the few times I need to rotate it, I have not pursued getting an L bracket for my main camera.

Also, let us not forget that we "pushed" some films back in the day so we could set our camera to ASA (the old term for ISO) to 400 instead of 100 and gain 2 stops. So, the gain that is electronically controlled is just an easier way of "pushing" film.

I have always liked Shutterfly. Easy to use. Upload your photos and put them in any order, 1 to many on a page (no limit on total photos - you pay by the page). Quality is excellent. I used to put together books of people I worked with and we would chip in to give one to whoever was leaving the team at some point. They were liked enough that we put together a final one that most people bought before we all were gone!

I stopped getting transitions when I got more serious about my photos. Can't see the info screen with them on (hard enough to do without dark glasses) and they also make it difficult to see the image in the viewfinder.

For personal use, or small batches, you probably can't do better than Michaels. Go and watch for their BOGO sales. I have rarely paid full price for their frames.

If you are going to sell photos and need to mount and mat a lot of them, look into RediMat. They have packages that include backing, windowed mat, and clear plastic envelope for each mat at a price you cannot match by going local or cutting them yourself. Even with the shipping from California to Connecticut, the cost per mat is substantially less than buying local (wish I could buy local, but apparently the suppliers around here don't get it).

Assembling your own frames from stock that you see in custom shops is also possible. Check out Grignons on the web for info on how to do it. You can get a much larger choice of frames and they are not hard to assemble.

Last, I sell a fair number of prints at craft fairs. I spent a lot of money framing some and displaying them. I have not sold more than a few framed ones, so now instead of lugging them to festivals, I just offer the option of framing.

I had this issue with someone I sent pictures to. It turns out they did not understand Dropbox and instead of DOWNLOADING photos, they were right clicking and copying. Yikes! I am thinking of always sending some instructions on how to download, just in case, when I send via Dropbox.

Crop only for composition, keeping the original format (whatever size your camera produces) and later, crop for prints you order. I use Lightroom, so I never lose the original photo, and when I print, I crop to the paper I am using. In PSE, you would probably have to do a "save as" from your uncropped photo (and don't save the crop to the original) for each different print size you might make.

Also, note that many printing companies now have "digital formats" so your out of camera crop can be printed directly.

I leave mine on. Being very nearsighted, I can't just adjust the diopter for no glasses. I tried contacts for a few years, but am now back to my glasses.

Go to DpReview.com and read their reviews. They have already done what you are proposing in great detail (more than you can possibly digest). You can compare shots of the same scene in various ISO's and see what noise will result - and much, much more.

Going back to film days and for a long time in digital, I shot at the smallest aperture for the most depth of field I could get. Now I understand the value of limiting DOF in some shots.

16MP will work fine. I have 24X36 and larger prints from all of my cameras ranging from 8MP to 20MP.
Only I can tell which one was which.