Teaching at an international school in Japan as a foreigner

I have a hypothetical question that I'd like to hear your opinions on!

How does one become an elementary/primary school homeroom teacher at an international school in Japan?

If I were to have the following qualifications, would a job as a HRT in an international school be possible in the future?

• BA degree & 3 years work experience in an unrelated field
• 2 years as an ALT on the JET Programme
• MA in Primary Education from a UK university + 1 year experience teaching in a UK primary school

Based on what you know/have heard via others, does a future working at an international school in Japan seem possible?

How do things work in terms of VISAs? Are international schools less likely to hire foreigners if they have to support their VISAs?

Please share any stories / advice etc you may have!

Thank you!