HCMC consulate is known for asking this. Look at the other posts over the past few weeks. Did you say on your application that you were employed in any way?
Yes. It has happened a few times. However, they usually tell you that they are giving you a tourist visa instead. They have the right to do whatever they want. Other option is they could just deny you anything, which is probably what they would have done if you said you didn’t want the tourist visa.
500K Baht equivalent is one of the core requirements for a DTV. Furthermore, I do not think swim is a covered "soft power" - Usually the trainings/courses covered relate to something Thai specific such as Muy Thai, Thai botany, etc.
Sponsorships have been hit or miss. Some embassies only let your employer be a sponsor, etc. it is best to reach out to the embassy you will apply via and ask them what they accept and what they need for this.
The Thai embassy in Cambodia takes 11 business days to process. They are usually good at keeping that timeline. Today was the 10th day. However, not sure if last Wednesday was a holiday or not for the embassy.
From their website, it sounds like you have to be a citizen or a resident of Spain or Andorra to apply via this embassy. Are you a citizen or a resident? (Non-Thai nationals, including citizens of Spain and Andorra, and other nationalities with residence in Spain and Andorra, who wish to apply for a Thai visa must apply and submit the application through the new online e-Visa platform)