How can I pull off being two two separate characters at the beginning of a campaign?

I will be playing a Changeling in an upcoming campaign (homebrew setting). I’m interested in hiding not only my race, but also having one or more "retainers" — alternate identities / personas that my changeling can slip into and out of as needed.

The catch is, I wish to conceal (at least at first) the fact that the PC and the NPC retainers are actually a single entity! The most straightforward way of doing this would seem to be observers seeing "both" characters arrive to the starting town at the same time. I would want this to deceive NPCs and fellow PCs.

What magic / mundane / class features do I need to pull off such a deception at level 1? If not, what’s the earliest level you could realistically pull the wool over NPC eyes, solo? The ruse must be able to confound casual observers, but bonus points if it can stand up to additional scrutiny!

I don’t have a set class for this character, but am leaning towards Bard, Rogue, or Wizard. Since I’m trying to fool the party as well, count on no help from them.