In both cases you're eligible for retirement visa. Also you are entitled to retirement visa and dependent visas (this maybe useful because retirement visa has some requirements about proof of income). A retirement visa is valid for 90 days but can be extended for 1 year. There are some requirements to the retirement visa and some paperwork. The requirements vary by passport and if you are applying in-country or out of country. So look at both of those options.
Also, you can get a 60 tourist visa which can be extended 30 days given you a total of 90 days. You can do border bounce which is probably 30 days with a extension of 30 days for a total of 60 days. (I am not sure because I am more familiar with US national visa options which may be a little different for Aussies and Japanese).
I have applied for and gotten my eVisa while not in my home country. There is a lot a debate if it's possible or legal or whatever. From personal experience, its possible to get an eVisa while travelling from Thai Embassy USA, maybe the is the case for Aussie/Japan. If you can, then you can have a eVisa for your second leg of your journey which gets you 90 days.
Netflix works, kinda. Thailand has some censorship laws so sometimes some movies aren't allowed. Additionally, Netflix will think you're in Asia and therefore show you a lot of Asian option (kpop, Thai dramas, etc).
There is a device you can buy that gets you access to a lot of viewing material for free. Its basically a device that downloads and plays bit torrents.
I manually download bit torrents and watching them on my tv, but that can be a pain if you're not technically inclined.
Rent for a year get a feel for what you like. There are different neighborhoods here and each have their own characteristics.
Foreigners can not own land but they can kinda own the company that owns the land. They can also lease the land for 20 or 30 years (I am not sure how long).
We have Bangkok Hospital in Pattaya which is foreign friendly. I am not sure I would choose that place for serious medical treatment (cancer, major surgery) but it's plenty modern for most medical needs, most doctors speak English.
The heart of Pattaya is party central, the further you get away from that the nicer things become.
Sonkran may cause you some issues but if I were in your situation I would use one of those services that run you to the border and bring you back. In Pattaya it takes about 8 hours round-trip, cost about 3500. You can do it yourself but those service usually know the best way, which counter to use (or not use), etc. etc.
Now see... I will be going out this weekend. I live in Pattaya and I have always had a blast going out at the same time everybody else celebrates songkran. However, I am told that pattaya observers Songkran the following week and it seems to me there is two weeks of water play here. I am usually done after one or two days.