CJK Letters some questions so I can compute font family sizes.

These are some basic questions about CJK characters.

Are they square?
Does it matter if we measure width or height?
Specifically,  will lr layout give the same letter spacing as vertical-rl?
What are the unicode-8 code sequences for visible characters in: Chinese,
Korean and Japanese?
Does font family vary as much in these languages as in Latin languages?
Wayne