For the real launch they've already mapped out the failure modes and are able to prevent them when it really matters.
One small BS detector is when there's some unplanned/unmitigated test outcome that gets characterized as a "test anomaly" rather than being transparent about the details.
>they've already mapped out the failure modes and are able to prevent them when it really matters
This remains to be seen. The shuttle also had all their failure modes mapped out. As did CST-100. Yet massive failures still occurred.
Mercury and Gemini both had good track records. Apollo and Shuttle, not so much.
Put differently, how much would you be willing to bet that their FMEA has caught literally every failure mode possible?
Regarding the foam, they had a difficult time even recreating it after the fact. It was apparently only on a lark that they decided to turn the gun up to 11 and, viola, now the foam had the physical properties capable of damaging the tile catastrophically. So, yes, they knew the mechanism of foam shedding but did not realize the effect properly.
With the o-rings, they similarly just didn’t have the test data for this conditions. They incorrectly extrapolated on the test data they did have.