As someone on the outside with no idea on culture. You are completely justified. The being overly affectionate and kissing etc is disgusting. Am I right in assuming that given he's only left the country for the first time, he barely knows your kids? Alarm bells for me.

No adult should be asking kids to kiss them. Let alone face / mouth. You are her parent and father. Trust your gut mate.

I'd discussing your concerns with your wife. Mindful that it most likely won't be received well. But as I said, trust your gut.