I fixed mine. A lot of stuff on this site is outdated. You need to extract debugserver from your xcode developer disk image for the iOS version you want. Then you need to sign it with codesign (access to all processes) so you wont get a "cant create thread" error, then you need to place that in usr/bin. You need to set the proper permissions(just chmod 755 debugserver in terminal) so you wont get a permission denied error. Then you can start debugserver and lldb from your mac terminal. I'm on iOS9.3.3, and this is also working up to 10.2 on any architecture. Goodluck.
Come to think of it, try setting the permissions for gdb(same command as above, just replace debugserver with gdb). Never tried it, but it might work.