Wading through all of this makes me wish I had either paid closer attention in high school biology
It's probably not your fault - there wasn't anything there to pay attention to in the first place. (I paid pretty close attention and never heard anything about the actual mechanisms of speciation.) I think it's a failure of high school biology programs that largely tip-toe around evolutionary mechanisms in deference to imagined creationists waiting in the wings to decend on the school.