I have been to immigration today to investigate this myself.. and was advised to apply to extend my 45-day tourist visa by another 60 days.. then apply for the married visa.. in the interim obtaining permission to open a Thai bank account.. in order to evidence requisite savings in an account in my name within Thailand.. except will also require my marriage certificate endorsed by overseas consulate.. since we weren't married in Thailand.. then have it translated and confirmed by Thai Ministry of Foreign Affairs.. before being able to register the marriage here.. and finally have the marriage recognised in Thailand.. it transpires that if i wanted our SG marriage certificate to be an internationally accepted document.. then i should have had it stamped/sealed in SG.. and then had a translation authenticated by the Thai Embassy in SG for registration in Thailand.. simpler and cheaper and a lot less hassle than trying to do it once you are in country and the clock is ticking on your tourist visa.. huge learning curve!

I guess it depends on who you ask.. since i was informed by Chiang Mai immigration staff today.. that retirement income would need to be confirmed in writing by the pension administrator.. they basically wanted a letter confirming the annual pension payment.. and never suggested tax returns as an alternative option.. or that investment income could be included in the calculations.. perhaps it depends whether it is raining or not on the day you apply.. lol 😆

I think you will find Singapore will not make exceptions for the 6-month rule on your passport.. even if you are only transitting through it to your final destination.. and the check-in staff at the airport are likely to stop you boarding.. having lived there for nearly 10 years myself I've found that there is little room for negotiation with SG authorities.. I'd definitely check with your airline before booking your flight if that's your preferred route.. just in case they have gotten soft in the post-koveed world!