i was wondering, what's the current passport validity requirement for the 30 days on-arrival and the 90 (60) days visas?

For travellers from countries allowed to enter without a visa:

Passport required (recommended to be valid 6 months after

period of stay. However, Thai Immigration will accept documents

which are only valid for period of intended stay).

To obtain a non-imm: p/port to be valid 6 months minimum

In any case I would make sure to have an extension or a new p/port before the 6-months period, as other countries in the area will insist on it.