I know the conversation has kind of gotten away from the original questions, but here are the answers to some of your first questions.
I write a blog about miniature horses and talk about training, grooming, massaging, braiding, and natural remedies. You should give it a look, maybe you'll find something that will help you? I just started blogging a few months ago so I don't have many posts. I’m waiting for it to warm up, so I can get outside to take some pictures for it. Here’s the link for it
https://ericksonminiatures.wordpress.com.
I've found that most minis really enjoy doing tricks and learn them pretty fast. I've trained mine to bow, kneel, lay down, sit, and stand on a pedestal. The time it takes to teach a horse a trick varies from horse to horse.
My all time favorite shampoo is Cowboy Magic! I've tried lots of different shampoos and conditioners, but none of them have preformed like Cowboy Magic. I have the Rosewater Shampoo, Conditioner, Detangler & Shine, Super body shine, Green Spot Remover, and Yellow Spot Remover. I highly recommend these products, they are wonderful! The detangler is amazing and will get out any knot, no matter what and keep knots away for weeks!
I think that braiding is one of my favorite things to do with my horses! There are dozens of braids you can do with your horses, on their mane, tail, and forelock. I find it very relaxing and meditative to braid my horse's hair. If you use braiding bands or yarn on your braids they should stay in a couple of days, of course their are some braids you wouldn't want to leave in over night.
I only use a bridle when I’m training them to drive or they have their saddle on, other wise it isn't really necessary to use it for anything else.
For Jumping I just use some cones or barrels for standards with pvc pipes or wooden poles. You don't need any “official” jumps, you can pretty much jump them over anything that is safe and collapsable.
There are lots of things you can do with minis! Just to name a few minis can jump, lunge, pull a cart, wear a saddle, long line, do tricks, do dressage on long lines, do agility and go to nursing homes and hospitals.
You can also do many natural therapies with horses such as massage, acupressure, stretching, aromatherapy, herbal therapy, and chromotherapy. I will also be writing more on my blog about each of these therapies and how to preform them on your horse.
I also love to paint on my horses, and they love it too, because I’m sure that it probably feels like a massage! I don't use any special equine paint I just use plain old cheap sidewalk chalk. I soak them in water for a few minutes before I use them. The paint comes out in the rain or when you give them a bath.
