You haven't told us the first segment, so impossible to give you hard numbers, but if you are booked on a Y-only aircraft, the ticket ought to price with that segment in Y. Might not be much difference, but it's unlikely to price as F. If you are concerned, call AA and have them price it for you as XXX-CLT-PHX-ANC with XXX-CLT in Y.

While AA used to rebook across tickets, that provision no longer appears on its customer-facing website. There is language in its TA-facing web pages, but it's unclear whether those were meant to be changed and the fact that those pages still contain the "disrupted" travel language isn't an error.

This isn't likely the occasion to find out.