Bro, some agents have told me that I can only have 60 days visa exemption even though I tell them I have a Chilean passport (we and 3 more countries have 90 days visa exemption).
They don't know too much about many things visa/immigration related.
that is not allowed since the DTV prohibits you to work with Thai clients in Thailand or for Thai companies. You will have to prove that you have clients outside Thailand, maybe have a portfolio and a website offering your services as an online personal trainer, I'm thinking something like that could work.