As to Dependent visa application, if you need my help, please let me know.
As to dependent visa, even if you have a job and working visa in Japan, it does not mean that you can get dependent visa for your spouse or children automatically.
From my experience, success case comes when
1 You can show financial stability of your household.
2 You can show you pay tax (and hopefully pension) correctly.
3 You can show your future life plan with them in Japan.
In essence, you need to show that you can make living even after your spouse or child (ren) come(s).
From our side, we need to persuade immigration office into getting permission to our application by explaining the above situation well.