OK, I think we need to run this through again:
The main genre for this RP is 20s/30s gangland. This in general can make this RP a crossover of real and film characters, serious and cartoony, and modified any way we like. We can use real individuals of the era, and any characters, live-action and animated, from any film, TV, and maybe even radio. To put it simply, it's mobland Toon Town.
Wikipedia is a good place to look up on real gangsters and lawmen, and if you want to touch them up, like make them furries and such, then it's fine. And there are plenty of shows of the genre and era. Here's a sample list:
The Untouchables
The Godfather series
Jim Henson's Dog City
All Dogs Go To Heaven (1st movie)
Who Framed Roger Rabbit (set in the late 40s, but similar genre)
Peter Gun (same as above)
Balto (set in the 20s, so it might fit too)
The Shadow (radio program)
some Looney Tunes episodes
a couple Tale Spin episodes
And others I can't remember...
Kor, your ideas work fine. You can only be limited by your own imagination. The only standards for this RP is the time era 20s & 30s, and anything gangster or mobster, and their polar opposites.