Resolved questions
兩點鐘 or 二點鐘？

You can write it either. They are both correct. But the pronunciation must be"liang".

两点钟

两点钟。we don't use "二点钟“ as the describe of two o'clock. it's just a custom.

两点钟.
使用2作为量词时:两 E.g: two apples (两个苹果)
使用2作为序号时:二 E.g: second floor(二层 or 第二层)
例外:20个苹果（二十个苹果）twenty apples.

people usually say "两点钟". they will understand you too if you say "二点钟", but it will sound strange. back in university my friend tried to be funny saying "顶了二下头" on purpose (hit you with my head twice) and that did sound funny.