It is not only 100 people per year, it is actually 100 people per Nationality each year. The 100 people per Nationally is based on who submits their application first, but I would be extremely surprised if any Western countries fulfill their annual quota.
there is no such thing as a ASEAN passport, the ASEAN group is made up from 10 South East Asian countries, you must still hold a valid passport for your home country.
we actually live in Cha-am about 20ks North of HH it is great a lot more laid back than HH, a great expat community, have been here in Cha-am for many years wouldn’t live anywhere else.