Since Latin-Han transform doesn't work, should get error on creation attempt, and should not include in enumeration
The Han-Latin transform is not reversible (and is so documented in the CLDR transform source file).
However, calling utrans_openU with "Latin-Han" and UTRANS_FORWARD, or calling utrans_openU with "Han-Latin" and UTRANS_REVERSE, succeeds with no error result. Using the resulting transliterator to attempt to back-convert pinyin output from a forward "Han-Latin" transform does nothing, it just leaves the pinyin untouched. Given that, it seems to me that the utrans_openU for "Latin-Han" forward (and for "Han-Latin" reverse) should fail.
Furthermore, the enumeration created by utrans_openIDs includes both Han-Latin and Latin-Han; it should probably not include the latter.