Are you actually on an extension of stay and not a visa at all? The difference is important so check your passport. Assuming your on an extension of stay you need to cancel your work permit and the extension the day you stop working for the Thai company, you can do this in advance with a letter from the company stating your last day of work. Same should apply to your spouse as her extension depends on yours. Then travel to a nearby country and apply for the DTV, once you have yours your spouse can apply for hers showing details of your DTV, marriage certificate etc
Your first step is to open a bank account, not easy but not impossible. If you get a residence certificate from immigration that can help as can someone of standing vouching for you. Other than that it's just a case of trying multiple branches of multiple banks until you find one that will, every branch has their own rules. Explain why you want it. Failing that go to a neighbouring country and apply for the 90 day non-o there, opening a bank account should be much easier but the residence certificate will still help.
You can't apply via the Thai embassy in Canada if you're not physically in Canada. You apply using the embassy/consulate that serves the area where you are physically located. So if you go to Cambodia you use the embassy in phnom penh
Anonymous participant ridiculous or not, inconvenient for you or not, that's the case. Get the paperwork to convert inside Thailand and the problem solves itself.