Force relaunch of Finder from terminal into background
The open command exits after it opens Finder. Even if it didn't, closing a shell would close background processes. You could try using disown:

/System/Library/CoreServices/Finder.app/Contents/MacOS/Finder &amp; disown $!


Or launchctl submit:

launchctl submit -l my.finder /System/Library/CoreServices/Finder.app/Contents/MacOS/Finder


launchctl remove my.finder removes the job.

Have you looked at log messages or crash reports? If you have tried to load or unload /System/Library/LaunchAgents/com.apple.Finder.plist, try removing entries for Finder in /var/db/launchd.db/com.apple.launchd{,.peruser.501}/overrides.plist.