Reiterating others that suggest a visa agent. I consulted with one when I first started thinking about relocating to Thailand. Now I use that agent for anything related to immigration. Saves a lot of confusion and is stress-free. Very reasonable cost considering I place a high value on my time.
The best solution is to do a one time deposit of B800k and be done with it until you have to show proof at the next visa extension in a year. Why do people want to try to make things happen perfectly 12 times instead of just once?
I'd suggest you get consultation from the moderator of this forum: Thailand Visa Advice. Absolutely get an agent involved to get everything sorted out. Not relationship advice to you but for everybody else that is reading this in a marriage Visa arrangement... take this unfortunate guy's situation as a hint of what can happen. Set up a Visa entirely on your own and not dependent on anybody else, especially a Thai female!
With these many questions I'd certainly enlist the services of a Visa agent. I have one that I use for anything immigration related. Ensures no time wasted and stress-free.
Getting the retirement Visa and "tie up money" is just the cost of the privilege of being long-term in Thailand with no issues. If you really want to be here then that becomes trivial in the whole scheme of things. You can get your money back if you discontinue coming to Thailand.