I done the Non O visa from the uk last year. applied online at Thai Embassy London. Got the 90 day visa. then opened a Thai bank account as soon as possible with 800K BHT and kept in bank for 2 months Applied for the year extension after 90 days in person at immigration office.
We had our cat brought from uk to Thailand. We used an agent in uk and Bangkok. All vaccinations up to date. Agent in uk dealt with passport etc by there vet. They collected cat from our home in uk and agent in Bangkok kept her for one night then transfer her to our home by temperature control van. And we used Thai airlines Not worth it for just a short trip. We moved to Thailand permanently
I put 800K in a Bank got extension for 1 year took 400K out after 5 months and have been putting 65K in bank every month by international payment . And then take out. I never go below 400K I will have 12 months of payments when renew extension. So I presume I don’t need to put another 400K in bank for 3 months