There is no claimed relationship (romantic anyway) so that defense would not apply. The bullying defense may apply for op if they do not redistribute in any way (including just showing them to others even without retransmitting them).
What i see is the girl could be subject to prosecution and if the op redistributes them in any way op could be subject to prosecution. I don't know how aggressive Texas or the local prosecutor is in this sort of matter but I have read of similar actions having been prosecuted in other states.
I suggest op be very cautious here. So often a young person ignorantly commits the crime of distribution of child porn by showing or sending such images to friends. If op retains the images they must be certain they show nobody other than when reporting said images to some
authority but it would be best if op outright deleted the images but still report this, at least, to op's parents.
I did not see either defense applying to what was described, either, but those are possible defenses to teens charged under Texas sexting laws.
In Michigan (and I know this does not apply to Texas), prosecutors are reluctant to prosecute teens for sending nude photos of
themselves to others. They will be offered a diversion program and ordered to complete X number of community service hours (sometimes with other conditions added).
Distributing nude photos of teens to others, however, can be dealt with more harshly (including the potential for federal charges).
It seems doubtful that quinn.brothers will be charged with possessing nude photos of the girl, unless it can be shown somehow that he encouraged her to send them (which he says he didn't) and, of course, depending on what the girl says. I don't know. But speaking to the parents, a school counselor and then an attorney if necessary seems to be pretty good advice.