If you want to keep with the Russian theme, I'd suggest:
Boris :-D
My favorite.
DimaFedorFilatIvanLev, if you're willing to go monosyllabic; it is appropriate, after all.
MironMotyaRurikTimur; comes with an interesting namesake.
ViktorMaksimPavel
Or other Slavic names:
Radek /
RadkoHavelKamilMarekFilipPenkoValko
Some of them are completely stereotypical, but since it's a cat, there's not much of a point in being subtle. :-P