I'd have to read the fare rules to be certain, but if it is a YUP (meaning full Y fare) they should be able to confirm you in Y on your alternative flights rather than fly standby. Depending on the F cabin load, maybe even confirm you in A. Again, I'd have to read the fare rules to be sure. But it's worth checking into for you.

As previously stated, many agents (and myself included until recently) think you can't standby over alternate connecting cities... but most of the fare rules I've read recently specifically allow this.