For ideass since some of the human audience will be country dance-knowledgeable how about taking elements to work in where you do little parts of line dance routines. There's something about a line dance that even people that never do it like to join in at a party or wedding etc. You can do the line dance parts or modify them and work the dog in as is easiest. I have seen people train dogs to line dance with their paws on the owner's hips. Very cute.
You might try little bits and parts of other dance styles..sometimes a song compilation is good for this where they or you combine songs into one routine. Maybe 40-45 seconds or more of each, waltz, two step, etc. Hearing different musk is ort of like starting different paragraph when it changes. People's interest is re-piqued.
The cuter the dog's costume is the more people will be impressed. Just be sure to keep it minimally covering so he doesn't get too hot and so that people can see him move and pick up his excited happy body language. Generally keeping your costume but more on the conservative side (not prude but no miles of sequins and cleavage) is easier for people to embrace esp with kids and conservative people there. Knowing your audience will probably help make your decisions about costume..
I started training this behavior with targeting too. Start moving your hand around to different height including high in front of the dog. I should be easy to transition your hand to a target stick so that you could stand to the dogs side and put the stick out in front and have him target. Add the voice cue and add your foot kicking just before you give the voide cue as a nonverbal cue. You should be able with treats and teach the dog to stand beside you and kick when you do.
The other idea which is how I taught my dog to wave. it might be easier to learn the kick is teaching a wave. I started out teaching target hand and gave it a word cue. Then I shaped the wave and shake. I kind of touch her foreleg leg too and cue wave c/t, then touched her other paw or foreleg and recued. I ignore the wrong paw and reward the right. Pretty soon she learned that alternating is what got the treats If you do clicker work and spend some time doing hand target click treat then just stand and wait and look at your dog click treat for any move of the front paw. Odds are if you have treats and the dog just finished targeting sort of high the dog will offer behaviors to see which ones get the treat. This is the perfect training chance to capture neat quirks and click reward them. Move front paw c/t, lifted paw.
Just remember for free shaping that a high rate of reinforcement keeps their interest and move around a little so they are forced to follow you. As they move you can c/t movement that is piece of that you want. With high rates of 3-5 seconds the dog stays engaged and offers behavior. If attention wanders reingage.