I would work on the bottle first. When I was ready to ease off the bottle, I would give my baby a sippy cup of milk right before bed. And I would do it without rocking or any of that other bottle-like routine. She didn't want that sippy cup. When she learned that she wasn't getting a bottle, but a sippy cup instead, she got over the bottle very quickly. Whatever you do , don't let him take the bottle to bed. That has a whole other set of issues. Besides rotting his teeth, you are introducing the bottle as a type pacifier, which only makes it harder to take away. And he won't be able to learn to self soothe on his own without a "prop".
You might find that the two go hand in hand. He may not go down easily without the bottle, leading him to have to cry. While some don't advocate for CIO, I find it necessary for the baby to learn to self soothe, especially at his age. Keep a journal going of how,long he cries each night. Otherwise, it will seem like an eternity, when it really hasn't been long at all. You will notice that it gets less and less each day.
Anyway, start with the bottle and see how it goes. Good luck!!!!