Re: Flirting with the hired gun, while on a date.
Excellent moves there my good sir! She was definitely giving out some strong IOIs, and if you wanted to you could easily re-initiate contact with her.
I would not read into the comment about the EX too much. You are right in that she probably brought it up to show she was single. Another reason was that she was also trying to contribute to the small talk. The idea that the purpose of pointing out her more mature EX could be a sign that she usually goes after more mature men could also be a possibility. However, if you play your game well, you could easily bypass this preference (If I am assuming you are around her age lol... no joke intended ).
I don't even need to ask whether you want to go after her or not, considering you graciously pointed that out in your post. I would highly recommend to message her on Facebook. To open, reference back to that fun night that you met her. Your first message should bring her back to that enchanting moment where you nearly brought her down to her knees in amazement. If she asks how you know who she is, tell her that the lady you were having dinner with knew you. From there, you have multiple interesting topics to go off of.
Overall, fantastic game. It's not surprising, since the content of your posts and your advice are of a high caliber. Have fun with this one!
"There is no better than adversity. Every defeat, every heartbreak, every loss, contains its own seed, its own lesson on how to improve your performance the next time." - Malcolm X