According to diagnostics disk1 is the invalid and emulated disk now so if you restart the rebuild that is the one it should begin rebuilding. And in fact, syslog says it had already begun rebuilding disk1 but looks like you cancelled it. It will start over from the beginning.
Syslog isnt showing an unclean shutdown though. Is your server on an UPS?
SMART for disk2 looks OK. If you want you can try checking the filesystem on disk2 before restarting the rebuild, or you can do that after.
https://wiki.unraid.net/Check_Disk_Filesystems#Checking_and_fixing_drives_in_the_webGui