I know with co-op, a lower-level character can fight higher-level enemies than they usually would have access to, so-long as the host is the higher level.
I don't have access to my copy right now so I can't test this myself, but is it possible to host for someone that's never even started the first mission, bring them up to a higher level, like 6, and that way the partner's Welcome to Helios will have Level 6 enemies, loot, and maybe unlocked vendors?
Like how grinding to levels like 5 or 8 in the Station, means that Serenity's Waste is a higher level compared to regular progression, but this question is asking about achieving the effect for the tutorial section of the game.