Fishtape is meant to be pushed through a conduit so that wires may be attached and pulled through (if you've ever tried to push wiring through a conduit, you'll know why it is such a great invention
)
Based on that, I would think that your second option would be the best, to push the tape up from the crawlspace and pull the wire back down. I installed phone wiring in my house this way, pushing the tape from the attic down the wall, then pulling the wire back up.
Either way, post back as to what method you used and how it worked out. (Oh, and enjoy the new audio setup
)