[PumpkinSpice]

That's gonna be tough with phonetics across several thousand languages... not to mention regional slang and other subculture stuff. I think the surest bet is just to avoid short names. If it's four or five letters, the likelihood of a collision is high. Stuff like Josephine, Gabriella, or Nathaniel is probably pretty safe.

Most of these are commonly shortened and then you're back in the danger zone, but then, at least you have the option of reverting to the long form without jumping through any legal hoops.