[SSJup81]

1. You'd need someone to sponsor you in order to obtain a work visa, and for most cases, you need a four-year (or three-year, depending on where you're attending) degree. The other way around that is having many years (a min of ten, iirc), of experience in the field you'd like to work in. That aside, what parts specifically confused you about the whole visa thing?

2. I don't know of any, but seems the most logical thing to do, would be to go to college, get a degree in whatever field interests you, hope to get a job with a company that also deals with international business and hope that one of those countries is Japan and maybe apply to work in that particular branch if a job opens up for it.

3. I have no idea, but I'm sure they are, just as long as you follow the rules and all that, but that pretty much goes without saying regardless of where you go, right?

Anywho, what field of work are you actually interested in? If you want to work in Japan, no matter where it is or what type of a stay, you'd still need a work visa.

I'll leave this for the more knowledgeable people. This is just my opinion on the matter. I feel that the best choice, given your age, is to just go to college so that you can focus on a career first of all. In your post, you didn't mention anyplace what you actually wanted to do, aside from maybe working in a store or restaurant. Unless you probably come across an English-run place, I doubt you'd have much luck here. I'm quite certain that you'd need a high Japanese proficiency level because you'd have to communicate with customers in Japanese.

Anyway, you should check out this sticked thread. You should read through it if you haven't had the chance to yet.