First thing, it reminds me of Umbreon, a Pokémon. Now, Pokémon is pretty popular, and I don't think it'll go away anytime soon. Also, the Eveelution line (of which Umbreon is part of) is a pretty popular line of Pokémon. A kid name Umbriel might get a lot of Pokémon references, maybe some teasing.
Next, I had to look up if Umbriel is an actual name. Apparently, it's the name of one of
Uranus' moons, as well as a sprite in
The Rape of the Lock, a poem by
Alexander Pope. And I'm pretty sure that Umbriel was a male, and I wouldn't be surprised, as Umbriel does look masculine. Why not
Ariel? It's another of
Uranus' moons, and also a character in said poem. It keeps a neat connection, but is not quite so out there.