Your planning is a bit...off
Thailand, like most places in the world that aren't in North America, uses IEC style nomenclature and wiring, from what I can tell (the actual standards aren't available in English, but the two threads I found on the topic on a Thai expat forum are thoroughly steeped in IEC terminology, such as RCD/RCBO, metric wire sizing, 400Y/230 LV distribution everywhere, and so on). As a result, 15A isn't even considered a standard breaker size, and Thai wiring rules apparently limit 1.5mm² to 10A anyway, with 16A circuits requiring 2.5mm² wire instead.
Given this, and the fact that Thailand, while having a legacy of using NEMA 1-15/5-15 plugs/receptacles (which is wrong, since those are a 120V config, not 220-240V), now uses its own plug standard (considered a "Type O" in the IEC taxonomy) rated for 16A/230V, you'll want to run your general appliance branch circuits as 16A circuits with 2.5mm² wire. You may be able to use 10A circuits for lighting, though, so do check with someone locally knowledgeable about that.
Wet area receptacles (kitchen/bath/outside) as well as water-heater type appliances will need RCD protection, although it may or may not required panel-wide, best I can tell. Eurostyle consumer units with DIN rail breakers may be permissible, although if you're going above about 24 breaker spaces, special IEC-rated versions of North American panelboard construction are available and may be preferable to the more traditional "consumer unit" construction.
Likewise, your service sizing will be...small by US standards. It seems that 30/32A and 50A are common service sizes in Thailand, with larger services delivered as three-phase. Speaking of large loads, note that that 2kW water heater will be perfectly happy on a 16A circuit, although the air conditioner may or may not require something larger.
Other than that, and any provisioning requirements the Thai standards provide, I'd provision:
- two lighting circuits (so that one trip doesn't wipe out the whole house's lights)
- a dedicated spur for the fridge
- two kitchen receptacle circuits
- a bathroom receptacle circuit
- a circuit for washer + dryer
- your water heater and AC circuits
- and circuits for bedrooms and living spaces as Harper describes (basically, splitting each room across 2 receptacle circuits shared between adjacent rooms)
Last but not least, Thailand apparently uses TN-C-S grounding, similar to what we do over here in North America.