Help me with my future dream

First , i've always addicted with japan's culture since i was young , and i'm building my dreams to live in japan , but in fact , living there is hard compared to other countries outside !
In my country , i can deal with three jobs daily , as i'm working as a college lecturer and an artist man ,
1- is that possible to have the same job there in japan ? i also work as a graphics designer , i can speak english fluently and have a good score at TOEFL ..is there any possible to work in my field of arts as a college lecturer and having art galleries there on japan ?
2- which universities that accept international lecturers to work ?
3- would it be hard to have a small business (such as : character design classes , photography studio, art gallery) ? or what ?
4- my japanese language isn't good , would that affect my career?

P.s : please answer my questions and help me with my future plans to live there in japan , i will be very thankful !
thanks in advance !

Currently what subject are you teaching at college, and in what language? If you can instruct only in English, please note that demand for such lecturers is limited in Japan, as most colleges/universities teach their courses in the Japanese language.

You will need to have one main "full-time" job so that you will be eligible for an employer-sponsored work visa. Other part-time jobs such as doing graphics design or your own classes "might" be allowed under a separate permit. Setting up a business on your own will be far more difficult.