Everything else has been answered I think so just re:tail braiding, urgh don't braid for an event. I hate braiding, IMO it's a very hacky thing to do. Plus braiding can make them tense over the back as the dock is the end of the horse's spine. I prefer to just trim the sides of the tail, either clip or use a pair of good scissors (sharp but with blunted ends) to neaten the top of the tail up.
I really wouldn't worry about braiding, hounestly, VERY few people round here braid tails unless you're hacking. And usually those who braid are the little kids, a trimmed tail is classier in dressage/eventing IMO.