Not knowing where in the country you are, I'll go with what works well out west. Sound wise I'd probably go with a high pitched (younger) rabbit tape or a bird distress (Yellowhammer Woodpecker or similar) for the fox. Nobody likes a good fight like a coon does... you might try either a coon squaller or fight tape for them - or the bird distress.
Boombox will work, although far from the best choice. Continous calling is not as good as some breaks in the sequence (in fact, more breaks than calling), and that takes a remote unless you have the box right next to you. Box 20-30 yards away (upwind) is more effective as it takes the predators focus off you somewhat to let you get your gun up, etc. (and I know because I only call with mouth calls and so I AM the center of attention when they get close).
HTH,
Ladobe :bye: