need decipher with android crash reports

hi everyone, can anyone help me understand what is causing the following crash reports i received this week on android store(oh, the covered up part just contain my game package name)

1st one:

2nd one:

HERE is what i guess/think:

1st: its a random crash on some device with the older Unity engine. With the latest U5, the problem should go away(this is purely my guess, plz give me some hint if you see more from that)

2nd: its the known issue with the older FB plugin in which when user click to login in, but did not finish the login and close the login window, at a later time, user click to open the login window again,crash happen(i m 80% sure that is what caused the 2nd crash report, but plz correct me if you see more from that)

thanks guys