yes but you almost certainly can’t go and renew your drivers license the precise day you have 365 days left on your extension of stay so will always have less than 1 year unless you have a multi year visa. According to these rules less than 1 year means 2 year driving license.
I agree this is how it's written. I recently renewed my driving license in Phang Nha with about 11-months left on my visa and was told in advance I needed 1-year left. I got a 5-year driving license. I think they might just want to see a 1-year visa with a good amount left on it but obviously that will be subject to discretion of DLT on the day.
but most non-immigrant visas are 1-year so unless you manage to get an appointment the day your non-imm visa is issued it will always be <365 days and so just a 2-year license.
2) I promise you it's perfectly normal for people living in Thailand and employed in Singapore / HK (and I am sure other places) to travel to their office or other locations 20 times a year (I am one of them). They would just need a work visa / pr or citizenship in the country their firm is in. Yes the Thai stamps in your passport get annoying and yes it is exhausting but hey ho.
3) The OP's reasons for travelling 20 times a year are totally clear. He is going to Indo to see his family.
why would a remote worker not need to travel regularly? You work in Thailand day to day, travel to Singapore or HK for meetings or to visit your office. That's the pattern of half the remote workers in Thailand.
Yes, appreciate only one parent needs to be Thai but from memory friends who applied for Thai citizenship as an adult had to have both parents physically in the country as part of their application process, even if one was not Thai.