[I debated whether to post this elaboration as a comment but it would've been way too long, so I'll just add it as an answer instead if that's OK.]
In the years since the Q&A were posted, a book called Seinfeldia: How a Show About Nothing Changed Everything was published which contains the full origin story of Elaine's dance (and an excerpt of which is available here on Yahoo Entertainment).
Elaine's dance was invented by Seinfeld writer Spike Feresten (who indeed based it on the awkward dance moves of his former SNL boss Lorne Michaels), and he taught Julia Louis-Dreyfus how to perfect them on set:
Among the ideas [Feresten] pitched in his first season [on Seinfeld] was one based on his time as a receptionist at Saturday Night Live. During his first year in show business, the legendary SNL creator Lorne Michaels was his boss. Feresten had idolized Michaels, and now he found himself down the hall from the man. [...]
Feresten found that aside from answering the main phone line in the office, another of his duties was to man the door at the Saturday Night Live afterparties. As he stood at the door late one Saturday, he spotted his boss dancing. What he saw, as he later told me, was Lorne Michaels dancing as if he’d never seen another human dance before. The man heaved and gyrated to a rhythm only he could feel. [...] At that moment, Feresten realized Michaels was just another nerdy guy. It endeared Feresten’s idol to him and allowed him to look his boss in the eye with confidence.
In Feresten’s eighth-season Seinfeld episode “The Little Kicks,” [...] Feresten even got to give Louis-Dreyfus a little dance lesson during production, schooling her in the singular Michaels method.
As for Dreyfus herself, here's a 92Y interview where she talks about her discovery at the early age of 3 of how screwing up a dance can make people laugh, and suggests (in jest) that it may have contributed to Elaine's choreography later on: