IOTL, Chaim Witz immigrated from Israel to America in the 1950s, changed his name first to Gene Klein, and then to Gene Simmons, and became a founding member of legendary rock band KISS.
What if he had stayed in Israel, though?
Here's what I think
* Paul Stanley - makes it in music, anyway. That man's voice was amazing in the 80s, and he has natural showmanship
* Peter Criss - remains a local drummer who never makes it big
* Ace Frehley - maybe records a few albums, but never achieves the level of success he did in real life
* Eric Carr - very talented and nice guy, but it's harder for a drummer to make it without a band than it is for a guitarist, so who knows? Definitely a better musician than Criss or Frehley, though.
* Vinnie Vincent - apparently impossible to work with, probably doesn't go very far, despite a lot of talent
* Mark St John - had medical issues that made him difficult to work with, he could probably make it doing studio work only
* Bruce Kulick - does session work (he worked with Michael Bolton IOTL, so probably more in that vein - his work with Bolton included a tour in 1983)
* Eric Singer - just like Kulick, session work and possibly touring behind a solo artist
* Tommy Thayer - probably the same, or maybe stays with his own band, which was moderately successful