Sum up,in Chinese ：
1.拉 is used to stringed instrument which has to be played with a bow on bowstring.
2.弹 is used to musical instrument which has keyboard or strings and which is played by plucking with fingers .
ex.弹钢琴，弹电子琴,弹吉他，弹竖琴，弹琵琶，弹古筝.....and so on
3.手风琴：As an especial instrument,both 弹and 拉 can be used.
Because it has a keyboard and the action includes pleating and pulling bellows when it is played .