Keeping a non-mahram as a Facebook friend and conveying salaam to non-mahrams

Q: 

Can I keep a non mahram as a Facebook friend? If I don't talk with them unnecessarily & don't post any photo of mine? Will it be considered as zina for me? Can I give likes to the posts of non mahrams or will it be considered as zina? 

Can I give salam to my non mahram relatives? Will it be considered as zina?

Revoking the talaaq

Q: If a person asked a mufti that I used the pashto word "zan talaq" to my wife 2 times like to her hands etc. Does divorce confirm by this asking? 

If a husband calls his wife hand as zan talaq, what does it mean while the husband doesn't intend for divorce?