Oh, in our case, our vocative is mostly a relic of the past, so its use is fairly limited – mostly names and professions (f.e. gospozha->gospozho). We don’t really use it for inanimate objects or abstractions (except poetically, I guess). And, indeed, sometimes even in “local” names it’s hard to use, especially in short forms which end on on -i (f.e. Niki’s just Niki, unless you want to make it also diminutive and turn it into Nikcho or something, but that also implies a certain level of familiarity because of the diminutive).
P.S. Oh, yeah, Straight outta Compton in BG is Бандата от Комптън – The gang from Compton. It’s one of those hard-to-translate-literally titles anyway.