1. Thinking of either the 5020 or the Panny 8000U. We're likely to remain 2D users here. I'm leaning toward the Epson BUT I can't seem to figure out if it has remote focus, which I think the Panny does. I don't want to have to get up on the ceiling to focus.
The Epson will be manual focus, but if you let it warm up about 30 mins. then set it, your pretty much done. I did miss having motorized focus initially, but if you don't need lens memory, (which is the panny's advantage), then the Epson 5020 should be better overall, also keeping in mind warranty and replacement bulbs. http://www.projectorreviews.com/epson/home-cinema-5020/competitors.php
Coderguy did a great breakdown on these at http://www.avsforum.com/t/1391476/coderguys-top-projector-picks
if you haven't read his post.
2. Are these going to be quite a bit better than the 3020? I've read the reviews, but the cost is considerably more so I'm a bit hesitant.
If you could afford the 5020, then it will be the better image, especially where blacks are concerned, vs the 3020. I'd try to fit the 5020 into my budget.
3. Zooming: I set the 3020 in the room so it was neither tele or wide. Am I correct in assuming that not using the zoom either way is the best choice if possible? I'm wondering how it affects the PQ if I do so? It would be better suited to the back ojf my room (see picture) but I don't want to do that if it will degrade either PQ or light output.
Generally, the farther away, less brightness and ideally placed within the middle of the zoom range would probably be the best, but would you notice the difference? Maybe, depending on the viewing environment. With your thoughts of mounting this pj at 22', consider the need of a little higher gain screen, and try setting it up temporarily in both locations to see which you like better. Using, http://www.eliteprojectorcalculator.com/
and the 5010 as a guide, a 1.3 gain screen might be needed at that distance of 22' to keep up the brightness. Remember as you get more hours on it, the bulb dims and if you want to keep it in ECO mode, (quieter and longer bulb life), the extra gain will be helpful if you decide on mounting it further back.
4. The Elite screen I bought will probably go back. I think I'd rather do 120". 100" was nice at 1.78:1 but for wider stuff I'd like a little more. Should I consider gain for this application, especially if I go with the 5020 or 8000U? Gain on this screen is 1.2 I think.
The larger screen may need more gain at a distance of 22'. Check the calculator to see what brightness numbers would be, depending on where you finally decide to mount it. I think 1.3 looked ok at 22' and 120".
5. Can I get away with some kind of wall mounted shelf at the back of the room instead of a ceiling mount? Is 22' just too far?
You could wall mount it, and 22' isn't to far depending on the viewing environment, with no or very little ambient light, and a bright enough screen to maintain brightness. Just some of my thoughts for you to consider.