I can offer a little help, but that's an awfully broad set of questions...
1. I know of no press that handles shotshell reloading
and brass cartridge (rifle) reloading.
The shotshell reloading involves crimp dies for plastic, a rather large primer diameter, shot measure as well as powder measure, etc. As in brass cartridge reloading, there are relatively simple shotshell presses as well as more expensive progressive presses. A MEC press is around $150 and a Hornady progressive is $600. Also, these are generally set up for one gauge, I believe.
2. If you don't want to have to buy different equipment later, you have to do enough research to make a "type selection", considering your shooting habits. (I'll use brass cartridge equipment for this explanation, but it applies to shotshell reloading as well, for a second press.) Generally, you will be considering the advantages/costs of single stage vs. turret vs. progressive.
The single stage presses are easier, in that they only do one thing at a time. If you shoot only a few hundred rounds a year, but want them to be custom-tailored to your needs, a single stage can be just fine.
Turret presses are a little faster, because all the dies can be mounted and left adjusted. However, the press still only does one operation per handle stroke. These are faster than single stage, but not as fast as a progressive.
Progressive presses are the most complex, and can be quite time-consuming to set up. However, they are ideal for turning out thousands of rounds per year for competition shooters. It can be challenging to "break out" of the progressive operation for operations like case trimming (for rifle), especially with presses that have automatic indexing. Some reloaders keep a single stage press for resizing and do everything else on the progressive.
Nobody can make this decision for you. You might get lots of answers that recommend one press over another, and the points brought up may be valid if you are comparing presses of the same type. That is, single stage vs. single stage. It isn't valid to compare single stage vs. progressive, for example.
3. If you are reloading for a semiautomatic rifle, you will need to order a full-length resizing die. This is to prevent chambering problems. You should also get a cartridge headspace gauge, which is very useful for setting up the resizing die to the correct length as well as checking for case length (is trimming necessary.)
4. Reloading isn't all that difficult to learn, but it is a
process consisting of many, many small details. If you don't understand a detail, you can get into trouble quite quickly. Shooting forums with reloading sections, like this one, are a very useful resource. However, they are no substitute for reading the first 100 pages of a reloading manual. Several times. This probably doesn't qualify as "a ton of time", but it isn't something you're going to master in one evening, that's for sure...
5. How much time is required to reload x rounds depends on the equipment you get. As mentioned above, a progressive press is the hardest to set up and the most expensive. For this, you get the most output. Single stage presses are easier to use (generally) and cheaper. With this goes very low production.
I don't know if my rambling clarified anything or just made things look worse. I believe if you get a manual first and read the first 100 pages, things will be a lot clearer.
