I can give you a grammatical characterization of Tibetan so then you can compare its features with the other two languages and progress your research about typology.
Tibetan is a particular language with some relatively weird grammatical elements.
Its lexical dimension:
As in Chinese and Burmese the basic words are mostly monosyllables and the creation of ...
In many languages, for example Bengali, the word comparable to if is optional and frequently absent, whereas the word marking the apodosis (usually with a similar function to then) is mandatory, exactly the opposite way round to English.
Of course, it's dubious whether then has an inherent connection with conditionals in English.
As for the order of things:
"In conditional statements, the conditional clause precedes the conclusion as the normal order in all languages. (...) (Greenberg 1963: 84, #14)
As for the question if there are words for "if", "then" and "else" in all languages: No ...