The evidence (as far of as the semen and DNA) wasn't kept in ozark it stayed at the state lab where it was found to preserve the chain and evidence itself.
As far a the forensic file... I believe they left parts out, just like the semen in the vaginal swab, to preserve the case. We already know and it's been proven that the LE agencies have prevented the public access to a lot of the evidence found. Not only that but some rape victims don't always have trauma that show significant signs rape, some fight back others go with it to get it over with to try and survive it's one of those you have know idea what you are going to do until you are in that situation. For all we know (if the trauma evidence wasn't one of the things that was held out of public view) he could have locked Traci alive in the trunk in the beginning to leverage control over JB, the do what I want or I'll kill your friend and then you. JB could have realized that no matter what the rape was going to happen do the next thing you would try to to is just survive the night, together JB and Traci
