Sure you can. And this will be also legal income to support your 800k requirement for your retirement Visa. There's a little twist in the formulation and taxation of your payouts. You should talk to the Samakon office or a decent accountant on how to set this up legally just.
That would be a total overkill as they are entitled to apply together as a married couple and thus reducing the monetary requirement from 1.6mil to 800k. Where is the logic?
I'm not a teacher and I have never ever had to produce a Thai police clearance for anything,... not for my visa, not for my WP and not for my ID-Card. 11 years in Thailand. First time I hear of this actually.