Tiger - there's no one answer for the post-date liking thing.
I had a date with one woman last year, it went well, I liked her when we met, I asked her for a second date and she said yes. The next day I saw she'd 'liked' me or winked at me, can't remember exactly, but it put a grin on my face
Earlier this year I had a date with a different woman. Date wasn't fantastic, she annoyed me in several ways and I wasn't feeling 'it'. So I didn't ask her out again. 2 days later she 'liked' and winked at me. That didnt change my mind. It made it obvious to my lizard hind-brain that I could get her into bed if I wanted to, but I try not to do that when there's no potential for more.
Since then, the same woman has winked at me or liked me 12 times. It's just a bit sad and creepy now.
But that's my situation. I winked back at the first one, didnt at the second one, but everyone's different