I'm surprised that she didn't reprise this role after she made it big. Come back again to do this sketch as a one off thing during the mid 2000's, as sort of a callback to this early stuff. Grown up little sister lol.
Brian Stack wrote this, but Amy did this all without cue cards. If cue cards faced her, the audience could read them. They'd know what's coming next. It would ruin the bit. So she memorized this in a few hours.
These sketches are better than anything they had her do on SNL... In this kind of role, she can be completely free and unhinged, more like the MadTV style of sketch comedy.