Speaking recently to a senior teacher at a school here in Kampot (An American) I was surprised to learn that he's active;ly seeking Filipino teachers for his school. He finds them very professional and good at their jobs. Filipinos are paid the same as any other foreign teachers. Good to see a demand for Filipino professionals that bisn't based on low salary.
English and mathematics, I believe, from elementary upwards. Khmer is not necessary. One of their concerns, by the way, is that they have a lot of overqualified people from the Philippines.
Just sent the link to my sister in law, a widowed lady who is a very competent and dedicated elementary school teacher in Molave.