No the BD on the 6th is so far away from the 12th (and you'd not O for a day or two after that, anyway) that everything would be dead and gone by then.
Clear and watery CM is still fertile and you can get fertile CM even a week in advance of O. I have gotten fertile CM even as soon as CD 3 (while still having AF, even) for a CD 14 ovulation. So while it is fertile it doesn't necessarily mean you will ovulate sooner.

