Baan Thai immigration solutions. I used them and know others that have used them too, they were excellent. It was about 11,000 baht and they did everything, you just have to provide them with what they ask for and they do the rest.
I believe the new digital arrival card asks for an ongoing flight but I don’t know anyone personally that has done that yet. Would be keen to know if anyone has done this yet.
expect to get tested on your Thai language skills. A friend of mine had a half hour interview all in Thai before being allowed in. I know of several other being pulled aside and interviewed with 2 people being denied entry because they didn’t know the basics. 
from what I understand it is the basics like, what’s your name, where are you from, where do you stay in Thailand, what’s your occupation and how long do you stay in Thailand.
true but you will need to prove your language skills on re-entering the country or risk having your visa cancelled and told to fly back out. I know a few people that had half hour interviews in Thai by immigration on arrival.
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