Opening bank account from overseas

Cannot open account unless in Thailand.

Apply for Non-O visa in your country to visit wife.  Normally they are good for 60 days and can be extended for 30 days.  Everything is doable if you work quickly.

Open bank account during first week in your name only and deposit minimum of 400k baht.  Balance must not fall below 400k during two months prior to applying for marriage extension.

A few days before 60 days expire apply for 30 day extension.  While at immigration find out what documents are required for marriage extension.  This should give you two weeks to collect documents and photos required for marriage extension.

When you have 14-15 days left on 30 day extension go and apply for marriage extension.