It looks like the IMEI is 356987068271459 - is that correct? Do you want to try to find who'd registered that phone, or should I?
Also, have you tried holding down the home button from the lock screen to activate Siri, and said stuff like Who does this iPhone belong to? or Call Home, Call Mom, Call Dad, anything?
I had the sim card in the phone 2 days after, no one claimed it.. I called Apple and they couldn't tell me anything but sure, try. The phone reset itself I'm guessing by the iCloud, so no, none of those options are available.
So I left my number with apple and no one claimed it, funny part is, it's only iCloud blocked and not on the national black list.