Depends how you define "benevolent." There are plenty of ways to have all three, just that they all require God's morality to be different/superior/whatever to your own.
Yeah... the fun one for me went thusly: In order to be omnibenevolent, the argument held, God must maximally possess the
most fundamental good, i.e.
that good which enables all other goods. That which enables all other goods (or to be more accurate, all things, period) is
existence -- a thing must
be before it can be
something. Therefore the good of God -- the maximal, fundamental, good possessed by the divine -- is existence. In modern parlance, God is the fundamental particle (if we ever actually find it). Medieval theologians (or at least they're the ones I first ran into that were using this line of argument) basically stated omnibenevolence meant hardcore materialism -- the good of God is the good of existence -- and it gave me the giggles.
It also meant that the omnibenevolence of god is logically equal to
omnipresence -- saying that "God is good" had the same meaning as saying "God is existent". All good, all existent, etc.
It was a neat and hilariously irreverent trick. "We'e got problems with the divine not matching with human morality! Let's define divine morality as something categorically different from human morality! No one will notice~" Which, being fair, no one really did for a while
It's always been a good trick, if one that gets you smacked upside the head if you try it in a decent academic discussion. "I'm not talking about X, I'm talking about
X, see? Yes, they're the exact same word, used in the exact same context, and generally kinda'
insinuated to mean something similar, but they're actually completely different and utterly unconnected. Neat, huh? Solves alla d'problems!" And then your skull gets beat like a drum at a bongo festival, as it right and proper.