The People from Issue Six Were Cliffy's Parents.
Same hair color, unmutated...it's possible that they performed a heroic sacrifice to buy their son time and Cliffy escaped just as Scrappy's pack was flanking the house. He made it to the city where he met up with Scrappy. Scrappy, If he survives the monsters will have a full on My God, What Have I Done? when he realizes the people he watched get ripped to pielces were his Morality Pet's Mom and Dad. Cliffy, if he finds out, will have a Broken Pedestal and go into Heroic BSoD. Godzilla monsters will appear.
Or more specifically ones based off of the Kaiju from the The Godzilla Power Hour will appear, including Godzooky and Godzilla himself. Scrappy's Mainstream self's true comic book counterpart is not Scrappy... It's Cliffy.
Think about it: aside from a very biased and inaccurate feature film, some non-canon promos, and a bad future that may or may not have been real and has been long since been erased, when has mainstream Scrappy EVER shown hatred for Scooby? Or anything remotely close? However, Cliffy, on the other hand, while initially being terrified, is beginning to show a more pugnacious side...although a bit less...family friendly then before;...Cliffy...is closer in age, personality, and appearance. Cliffy is Flim-Flam
Cmon, it's pretty obvious...