If you were to lie on your Thai Elite application (they ask if you have ever been convicted of a crime or incarcerated) and it is discovered after you become a member, it would not end well....
It is solely owned by the TAT (Tourism Authority of Thailand) which has also been around for decades and is not going anywhere regardless of any changes in the government...
I joined Thailand Elite when it was first introduced over a decade ago and have been through a few "coups" since, the program has been unchanged throughout. I am a very happy member...
In my experience, some schools offer a variety of class sizes...ranging from private "1 on 1" to semi private, to small groups 3 or 4 students and larger groups. This allows you flexibility to choose what works best for you. Obviously the smaller the class the higher the course price which is divided by the number of students attending. Private being the most expensive but also offering the most flexibility.
Many years ago I did a TEFL course in Bangkok and taught English for several years....I also sat in on classes at severals schools before deciding. My program was 120 hours (4 hrs per day, 5 days per week), so it is important to feel comfortable with the instructors teaching style.