Handshake or face to face hugs & kisses?

Since I am in Internations meeting expats in my conservative country, I have got used to expats give face to face hugs & kisses with opposite gender for first time in each events include the lady expats.
It is not a norm in my country except in the case between family members and lady to lady friends.

It means to different people - norm, close friends or sexual. In business, handshake is the most formal.

If met first time in social event, should I do the handshake or face to face hug and kiss? Who should initiate first?

If met second or third time, face to face hug and kiss works but who initiates it first? What if the person is married or has the other half?

Without playing games, who should initiate it first?