Turkey brine question

It'll be fine. Just remember to rinse the bird well after removing from the brine. Many forget or fail to rinse the turkey and that's why most birds come out salty. Rinse the inside of the bird REALLY well. That with hold a lot of salt since it's in closer contact compared to the skin covered areas.

DO NOT inject or season a turkey that you brine w/ salt and sugar. I have had many family members do it b/c after brining it appears there is too little seasoning. Don't be deceived, you need nothing more. Try this one it's the best;

ALTON BROWN'S TURKEY BRINE

He already has the brine solution base.
And seasoning a bird after brining is perfectly fine if you want to add more flavor to it. Just use salt sparingly or none at all.
Could just inject with warm melted butter. Just inject the butter in many spots a little at a time to create pockets of deliciousness. The butter will solidify somewhat quickly going into a cold bird.