Looks like an NGV conversion not LPG. Storing cylinders like that is not the way to do it.. There are way to many accidents in Thailand of single story buses converted to two stories. Doesn't work.
Don't disagree with you but from 1st hand experience it sounds like the LPG in the cylinder did a 'BLEVE' most likely from being exposed from an adjacent gas flame. Quite common here.
No such thing as an International Driving License, it is an International Driving Permit giving translations of you normal license. If you are in Thailand for more than 3 months then you have to have a Thai Driving License.
Monorails are a total waste of money, they fail and breakdown frequently in nearly every country that has installed them. The only one that really works is in Japan.
The warning system has not worked for years and the systems etc. that were supposed to be put in place have never been completed. It is also almost impossible to protect against natural disasters 100% anyway.
I doubt for one minute that the shooting had anything to do with the reduced tourist numbers. more likely that China if feeling the pinch from lower income and money is not so much available.