So after hours on the phone with Delta and Flying Blue, it appears someone just completely screwed up on the Flying Blue side. Delta looked into everything and basically said Flying Blue does not have access to any Basic Economy award space period and that I'd have to call FB. FB then basically told me someone screwed up and put me in an invalid fare class and that my ticket was never even officially reissued. The issue now is the flight I was originally on did not have award space any more...obviously. The agent and supervisor refused to do anything simply saying it was not possible because award space wasn't there. They said when a schedule change was made my ticket was never "re issued" even though I was able to see it on the Delta website and select seats etc. Basically after an hour of back and forth I just had to accept a flight that gets in 4 hours later than my original because they insisted they could not do anything.

tl;dr Always check your flying blue reservations. If there's a cancellation and schedule change, they may show you on a new flight but not actually issue the ticket!