The names John & Cynthia Darling are a little nod to legendary cartoonist Tom Batiuk - John Darling was a short-lived comic he did a couple decades ago, and Cynthia is based on Cynthia "Cindy" Summers.
TRANSCRIPTION COURTESY OF JOSEPH HOUK - [1967; CW from 2006 is about to buy her home] (Past CW, to herself) How sweet is this. I'm buying a four-bedroom home in 1967 for the price of a 2007 car!!! (MG, offscreen) "Psst... Cassie Wells!" (PCW, surprised) "Huh? How do you kn... MATT? Is that YOU?" (MG) "Yeah... It's me a few years ahead from your time. You eventually buy a robot..." (ND) "Hi. I'm Nicki." (MG) "...And SHE has a message for you!" [Holoprojector AWAY!] (CW – the "current" one) "Hello, Cassie of 2006. This is Cassie of 2009. Please listen carefully, there's been a slight change of plans. Eventually Dad will want to see the title papers on the house for an insurance quote... so Matt, and Nicki, our future robot, are here posing as the people whose names need to be on the title now. John and Cynthia Darling. [John Darling is a "shout-out" to the comic strip Funky Winkerbean] And then, when you transfer the title in 2001, it'll be their daughter Nicki Darling that you transfer it to. Nicki will meet you at that point then. [PCW looks down at her papers for the house] Do all this now and we'll save ourselves a load of headaches in the future. (fading out) Thanks, and congrats on the new home!" [FZZZT] (PCW) "Now I know how Emmett Brown [Great Scott! It's a BTTF reference!] felt in 1955..." (ND) "Hell, I feel like R2- D2!"