I would go for another kitten closer to the age or maybe an older kitten, a teenager (in human terms). I think the introduction will be a lot easier with two kittens, and they'll also have the same energy level.
I have brother and sister kittens (will be "cats" tomorrow). They are high energy and great jumpers, but they spend most of their energy on each other, and mostly come to me for food and cuddling though I do play with them in the evenings too, and they now demand it every evening. They never grab my feet - they have each other for this, my feet are for rubbing on. They are also well-socialized and are very good in keeping their claws retracted all the time, even if they are annoyed with me e.g. when I brush them, they paw me with the claws in. I could simply be lucky with personality, but it also could be their socialization with each other, all the experience of play fighting. This by the way was apparent when I met them at the rescue - when I picked them up they stayed calm and kept their claws in and when they wanted to be let go, they pushed with soft paws.