Creating Kudu tables shouldn't allow types not supported by Kudu (e.g. VAR/CHAR, DECIMAL, TIMESTAMP, collection types). The behavior is inconsistent, for some types it throws in the catalog, for VAR/CHAR these become strings. These should all fail w/ analysis exceptions until Kudu supports these types.
Similarly, external tables cannot contain Kudu types that Impala doesn't support (e.g. UNIXTIME_MICROS, BINARY). This does fail, but we need tests to verify.