I would take the 18 f2 or buy the cheap Samyang 12 f2 (you'll need wide mainly for interiors and temples) and 35 f2 or 50 f2. The X100T is always a very handy small camera that covers 23mm, acts as a backup camera just in case and don't have to switch lenses all the time. That tele 50-230 could be useful sometimes.
I've been in Thailand 7 years ago on honeymoon for about 2 weeks late October and got some rain showers but not much to worry about - 1 week in Bangkok, North (Chiang Mai, Chiang Rai, Mae Sae) and other week on South. By then I was a Canon user and took 3 zooms - Wide, normal and tele and a small pocketable Panasonic LX-3 just for some videos.
Nowadays with my Fuji gear I would take the X-Pro 2, 16 f1.4, 35 f2 and a X100F. Probably I'd buy a tele like yours, is useful for some wildlife and some shots of people praying that you don't want to disturb keeping a comfortable distance. Have a nice trip, it's a great country to visit with very nice people.