Hi joseph,
I don't know if the two issues are related.
Based on the [guide|2183|teardown|page=2] (step 11), both cables are very close to one another and on the same board. You might want to check if the display cable is still 100% attached/connected on both ends. Based on the dead area of the LCD, it could be that the connection got loose on one side.
In regard to the volume button, I would try to solder back the one wire that is broken. Or, if this is not possible, you might want to buy a replacement unit like [http://www.ebay.com/itm/On-Off-Volume-Button-Flex-Cable-For-IPad-Wifi-3G-8-tools-US-/270984130062?pt=Other_Tablet_eReader_Accessories&hash=item3f17e9ae0e|this].
Steffen