You will still meet them later on depending on what faction to pick. And the third is by bypassing Unbound you will not be able to get introduced to the Civil War by Hadvar or Ralof. If you return to Helgen you will only find the imperials and stormcloaks have murdered eachother making it a ghost town with only a few civilians still walking around doing nothing. Three side effects of this method is you won’t be able to complete the tutorial quest Unbound, and to perhaps some the good news is Helgen will survive the dragon attack as we bypass that sequence entirely.
This will teleport you to Riverwood as a default Nord.
This is the quickest way for testing new mods, or simply starting a new game without having to play through the intro sequence and the tutorial quest.