Hello,
I also think you should stop buying formula, unless your son has an issue with whole milk which apparently he doesn't have.
As far as the baby bottle is concerned, I don't understand why you want to get to rid of it.
At 12 months old, my daughter still had her bottle for the morning, afternoon snack (and some apple sauce) and sometimes the evening. Daycare asked to stop the bottle but my daughter didn't like it (even though she would drink water from the sippy cyp). So I didn't insist = I wanted her meal to be peaceful, especially in the morning when everyone has to get ready to go to work. So, I replaced the PM bottle for some plain yogurt for daycare and she didn't have any problem. Lunch, snack time & dinner were solid food.
She never had any problem with the bottle = only for breakfast. At 14 month she wanted to eat by herself with a spoon and at 2 YO she would eat with fork & knife (baby size).
Now she's 2 and1/2 YO and she still has her bottle in the morning, during week days and on the weekends, she has a regular breakfast with us.
Good luck