You can replace characters by going into their costumes and replacing the poses with your characters' poses. You can also change some of the animation code if you want it to look different. (FLASHING LIGHTS OCCOUR)
Is anyone (anyone at all) surprised that I put Boyfriend and Daddy Dearest for this? I didn’t think so. Girlfriend/Boyfriend and Pico would’ve made more sense because those are actually unlikely rivalries but Daddy Dearest and Boyfriend are a classic FNF rivalry.