A Non OA is good for up to 2 years. Enter just before it expires and as long as you have valid insurance you’ll be stamped in for another year. This second year is not multiple entry. To leave and return you’d need to buy re-entry permits.
A year extension is available for a Non O or a Non OA providing you meet the financial requirements (800k for two months prior). The difference is that the OA would also require a year of health insurance that meets the requirements (basically a Thai company nominated by immigration). The Non O does not need this requirement.
Those approaching 70+ find it very expensive or impossible to get coverage for that age.
Yes if you have legal residence in a country it’s equivalent of being your home country.
The Non O is usually the easiest path. It gets you 90 days on entry, then you have a month to set up a Thai bank account and deposit 800k in it for your year extension- funds need to be in 2 months prior to applying for the extension.
The Non OX is only available from your home country (I know it says it can be got in Thailand but I’ve never heard of a single instance where that’s happened).
Almost no one applies for it because of the stipulation of 3m baht in a Thai bank account.
The consulate in Sydney is the only one in the world that would issue one with local funds rather than in a Thai bank so I would guess that 99.99% of holders of one got theirs from Sydney.
The first few days of accommodation should be fine. If they ask for more book a refundable hotel and cancel when you have the Non O.
There’s nothing to check. A visa is valid from the date of issue. If you apply for a 6 month visa 3 months ahead of time then you’ll just waste 3 months of its validity.
Depending of the consulate or embassy you use then check their normal turn around times.
For example London is about 3-5 days. LA is about 10 days. France or Germany is about 3 years. (Well ok that last one is a bit of an exaggeration but it feels like that for those that use them).