IAU = Millau (one of the founders of the Gault Millau guidebooks for travellers).
Anyone can find a better one, I imagine. For some reason, I found this one hard.
IEA
CRIMEA: obviously where the Crimean War took place[also see balaclava and cardigan]
IEE
Thread rule: it doesn’t count if it is also a common noun, such as “Turkey” or the Soundargarden song “Entering”.
IEE = Irene
IEI?
How about two tire makers: Michelin or Pirelli.
IEO?
IEO = Hideo, as in Hideo Nakata, who directed Ringu.
IEU?
That’s not the way I read the OP. A lot of ordinary words have been used as proper nouns, look at all those classic names like Prudence (UEE), Charity (AIY)* and such. Seems to fall under the qualification given by the OP. Note in particular that the name comes from the word (in Latin).
Perhaps you should have assumed that since I looked it up in a dictionary that I am not a complete twit and not used such language.
And speaking of “Y”…
SILENUS: Greek mythological character, a principal in the story of King Midas.
IIA
IIA = Indian
IIE
Ithica (New York)
III
William
(indian is also a common noun. Ithica, NY is actually spelled Ithaca)
But, it might actually be Ithica in Greece.
IIE?
Minié, as in Claude Minié: Famous Impressionist painter. 
No, no, he actually invented the shaped bullet called the minié ball.
III
I would have gone with “Mini Me”.
Rin Tin Tin
IIO?
VISIGOTH: as opposed to an Ostrogoth.
IIU
Respectfully. . .
visigoth (a noun signifying a member of the tribe) can also be thrown in with Visigoth (a name signifying the tribe), so it kind of breaks the rule.
Just as “German” wouldn’t count if there were an ea, though Germany would.
I know it seems silly but it is what distinguishes this thread from the other.
How about “Indio” a california city.
(or Inigo, as in “…Montoya. You killed my father. Prepare to die”)
iiu?
Milius as in John Milius, director of Conan: The Barbarian.
IOA?
IOA: Iowa!
IOE?
IOE – Niobe (mythical queen of Thebes and daughter of Tantalus)
IOI?
IOI - Zionist
IOO?
How about Zionism to stay within the rule?
I don’t think we accurately policed this early on (e.g. Nepali) but I’m turning into thread nazi before we get orange for OAE.
IOO