I've also had both of those answers...the one for "Oahu" was "Diamond Head locale," I think? And the one for "uke" was "cousin of the mandolin, briefly."
It's so exciting!
Edit: Just found "Lanai" as an answer to "Island near Maui." I'm liking this crossword!
Yeah, Hawaii terms are pretty popular. I've seen "lei" and "maui/oahu/lanai" used a lot..."hula" is another popular one. It is almost definitely for the vowels. French terms are even more popular though.
Crosswords are awesome, even though I can't do anything past Wednesday.
Hate to be a crossword nerd, but that's not a very good clue. IMHO. If it's three letters, then the answer must be "uke", which is short for "ukulele". It's common practice in most of these cases to put some hint in the clue that they are looking for an abbreviation or "short" form.
Like: 5 Down inst.
Or: 5 Down instrument, for short
I bet Will Shortz would never print a clue like that.