Thanks for posting!! It sounds like you have a lot of things already figured out for your room, which is great! I made a video about DIY Gallery Walls that focused a lot on placement and positioning, so maybe that could help you figure out where and how you’d like to hang your frames!
As far as incorporating purple, but not making it overwhelming, I would advise playing with different shades of purple. Don’t just pick one tone and repeat that, but have a variety of purples from pastel to eggplant. Some pillows, a little bit of art, or even an area rug in purple tones are all nice ways to integrate the color without letting it take over.