tm30 is being enforced in CM. The immigration Facebook page has regular reports about immigration officers visiting various locations checking that tm30s are being made on all guests and visitors
There's no medical certificate or police report required for in-country applications or medical insurance for that matter (which may or may not be applicable for an ASEAN member), so not sure how, but whichever option you choose, it's always worth knowing the pros and cons of each process 😁
Generally speaking, it's much easier to just fly into Thailand on tourist visa or visa exempt and then apply to convert to Non-O in-country. Plenty of threads on how to do it
I read that CM DID require a TM30 after returning from abroad. The justification was that they needed to correlate the TM6 number with the TM30 but since they've effectively abolished the TM6 not sure if they've changed policy again
If you're questioned why/how you're on holiday during term-time, you'd definitely need a letter authorising you to be away from class. I didn't say it's something that always checked, but it has been reported as an issue for some people over the years so it absolutely is "a thing". With respect, simply because you haven't heard of something does mean it doesn't exist. Like they say, something isn't ever a prone until it's a problem. My school didn't even tell me I needed a letter cancelling my ED visa, and I left Thailand and returned without any questions from the IO but at my next extension the IO insisted on getting the cancellation letter. Just shows that there's not always consistency amongst IOs (or schools for that matter)
Need to check requirements for 'seasoning' of funds for first application. Main advantage of doing the VE is no requirements for health insurance. Speak to an agent if unsure but most if not all requirements are online these days. I've never done the process. I converted from ED to Retirement in-country