1. There are 2 "Color" Sections and one section reserved for dining packages(not picnics). The Blue is considered the best section as it is most "center" to the show. Yellow is still good but if you are on the extreme right side of the yellow you will loose out on some of the show.
They issue FastPasses in a specific order. First Blue, then Yellow. If there are more than one show they issue them for the first show, then the 2nd, then the third(rare). So for example they will issue them in the following order 9:00 Blue, 9:00 Yellow, 10:15 Blue, 10:15 Yellow. On most days there are still FastPasses available well into the afternoon but it may be for the later show in Yellow. However, there have been several weekends when we can still get 10:15 Blue after 4PM. So it really just depends on the exact day. But if you are looking for the first show, the "Blue" section often is gone in the first couple of hours. Early Admission does not matter as they do not start issuing FastPasses until the official park opening.
2. You don't get a reserved "spot", but you will get a guaranteed ticket to the first show. Most of the time it will be for the Blue Section, but if you get there later in the afternoon it could be for Yellow. It CAN be a good option if you must have the earlier show and you are not going to be able to make it to the park earlier in the day. But if you are open to the time you can go, and can get there reasonably early and nothing on the menu sounds good then save the money and just get the FastPasses.
The food is "average" at best. For us it is enough for a lunch, but if you are not a big eater it could be a dinner. For us the fact you got a reusable shopping bag was a better perk than the food.
3. The viewing area is "tiered" and the first tier closest to the water is generally an area you will get wet. How wet you get depends on the wind. There have been times when we have been in the front and didn't get wet at all, and there are times when we have been further back and got wet. But most of the time you can expect to get at least a little wet. Think about it as a heavy drizzle. It isn't enough for me to consider wearing rain gear, but I have seen some people do it..so it is really just a matter of your personal preference.
I don't know how much of a visual impairment your friend has, but if you are worried about getting wet. If you get the "Blue" section part of that includes the bridge(you will know what this is when you get there). Here you can be fairly close but are also above the bay so your chances of getting wet would be reduced. The distance would probably be equivalent to the 2nd tier in the main area.
Now, some other things you didn't mention but probably should know. You do not need a FastPass to see the show, just to get into the reserved area. There are several areas that you can see the show without a FP. They won't be as good but still okay. If they have more than one show the 2nd show is going to be less crowded.
You don't say how early you plan to show up, but getting there any earlier than 60-90 minutes before is pretty much a waste of time, and even the 90 minutes is excessive on just about every day. Before the first show they clear out the area and do not let anyone into it until about 45-60 minutes before. There are people that queue up outside the area before, but not much before that 60 minute mark. Now, for the 2nd show you will be queued up in an area away from the Paradise Pier area. People often start to line up as soon as the first show begins, but again getting there about an hour before will pretty much guarantee you a great spot. We often don't show up until 30 minutes before and still get a good spot. However, if you do have a very specific spot you want to be at, then you probably should plan to arrive a bit on the earlier side.