I can only tell you something about Phuket, not the other diving areas.
First: finding work as a DM is not easy, as an instructor you are much more flexible and so much more employable. Then you will have to take into account, that it is quite difficult to find a job as fixed staff, for sure in the beginning you will have to work free lance. As freelancer guiding: depending on who you work for 600-800 Baht for 2 dives a day. As freelancer instructing: this really depends, some companies offer 10% of the course price + 500 Baht per day, others 30% of the course price, others have fixed amounts, e.g. 2400 Baht per student for OW, 1900 Baht per student for Advanced, etc. And some make a difference in the number of students, e.g. 3000 Baht for the first OW-student, 2200 for the second.
On liveaboards: I think at the moment the maximum pay is 800 Baht per day (free lance), with the good thing that there is no way to spend the money.
Fixed staff: depends on the company again, some pay fixed amounts, others commissions, most a combination. In total it will be in the 30,000-40,000 Baht range, a bit more in the high season, a bit less in the low season.
