Hi Steve,
If the rootstocks are still alive and you have green cambium, you can either chip or T bud them immediately.
One of our more experienced members: Fruitnuts, posted this T bud tutorial: T-budding tutorial
If that fails don’t give up, try green scion grafting after early August. You have many ways to graft apple so I’m sure something will work for you. Contact me if you need more discussion.
Dennis
Kent, Wa