Ok, first some fundamentals;
1. Cable is sized to provide the required full load current at rated voltage for the end consumer.
2. MCB is sized to protect the cable (not the end consumer)
3. All cables have a maximum current carrying capacity based on voltage divided by resistance per Km (R1+R2). Cables are then derated based on ambient temperature (typically standard ratings are based on 20 degs C), type of insulation and installation method.
So for your 1.5mm 2 core PVC insulated cable recommended maximum load after derating for temperature at 30 degs C (because we're in Thailand) PVC insulation and installation in conduit enclosed in a wall is 12.64A. As stated above the MCB needs to protect the cable so MCB should be either 10A or less.
Similarly your 2.5mm cable maximum load should not exceed 20.6A and be protected by 16A MCB or less.
Maximum load for 1.5mm circuit = 220V*10A= 2.2kW
Max load for 2.5mm circuit = 220V*16A= 3.52kW
All MCBs are designed to operate without trip up to 1.15% of their rating
Hence all your loads that you have stated will be okay based on 10A and 16A MCBs.
As for earth fault/leakage protection this is another ball game in Thailand, first you need to ensure you have installed a functional earth system with enough earth rods to achieve a earth loop impedance of less than 5 ohms to enable your RCDs or RCBOs to trip in less than 0.4 seconds when installed in circuits requiring personnel protection (showers, hand held appliances etc.). Suggest you get a reputable sparky who knows what their doing to check this for you otherwise consequences could be.......well not good.
My advice would be to buy consumer unit with enough capacity for all consumer circuits plus 25% spare. Fit all socket, shower and water heater circuits with dedicated RCBOs, all other circuits standard MCBs. Alternative is split phase board with RCD protection and standard MCBs.
DO NOT buy one of those Safe-T boards, use only good quality reputable branded products.
Hope the above is some help.