That is some severe damage to the bark on the trunk. Is the live bark along the edge of the exposed area attached and growing? If so, the tree has a good change to recover. 

The wilted branch does look like fireblight. Are there many branches that are wilting?  As the website directs you to prune out the wilted/dead branch 8" below wilt. Be certain to sterilize pruners between cuts. Properly dispose of all removed branches. 

This tree is severely compromised so it may develop black rot. Pamper your tree and  be sure to water it this season whenever it is dry. All of this will help the tree survive but no guarantee that it can recover.

Thanks for the question. Good luck.

The die back in the terminal branches is likely fireblight. You need to cut those out so that the bacteria does not spread. If not managed, it could kill the tree. You ask a good question. Severe bark damage and the drought could cause dieback in the upper branches, in which some upper branches would not leaf out in the spring or would leaf out sparsely with smaller leaves. It looks like your tree leafed out and then died back.

No need to remove larger branches. This would stress the tree more. It needs all of those leaves to photosynthesis and grow/heal. Yes, open wounds are not desirable. However, the research shows that the tree will heal them without any paint or tar or....any other dressing.

So sorry to hear about your loss. This tree is special so hopefully you can save it.

Paul 

Tree Care Advisor volunteer