It's known very well already. Transfers into Thailand from 1.1.2024 are assessable for Thai income tax. Unless your country's DTA exempts your pension, for example. Even then, any liability to Thai tax can be offset by tax already paid on that money
In northern mountains in Winter, maybe some nights would be cool enough. But most nights I think you'd still want at least a fan. BTW here at the coast in Chonburi, I manage with just a big ceiling fan in my bedroom. Very rare I need AC on at night
If the house owner will not file TM30 you need to contact Immigration Office for advice. You won't get an extention if you are not registered at an address via TM30
Nadia I'm sorry, people are right when they say you can't easily do what you want to do, to live in Thailand. You might find jobs as English teachers if you get a TEFL qualification, but teachers are not well paid here.