I will have a horse party. Correct!
I will let them (?) dance, eat, watch TV on the horses.
~> I will let my friends dance, eat and watch TV on the horses.

you can name them keep them braid their manes, and best of all you can ride the horse to school.
~> They can name them, braid their mane and best of all, they can ride the horse going to school.

I love horses.  Correct!

>>> I will have a horse party. I will let my friends dance, eat and watch TV on the horses. They can name them, braid their mane and best of all, they can ride the horse going to school. I love horses.