As a small update, I ended up doing both in first person. I ended up finding a thread on Goodreads which broke down novels that succesfully used different perspectives, and most of them had something like one first person, along with multiple third person. What really sealed it for me was someone said they enjoyed a novel that went first/third. BUT the reason it worked is because the third person was the villain, and it gave them a feeling of distance from that POV. I hadn't considered the different between intimate/distant, so that decided it for me. Both stories will be in first person.