Well, a dispensable novel is different. That's not either franchises primary form. The compendium of video games, novels and comics are minutiae.
But Fox would still have no problem retconning A3 and A4. Ripley's back, "From the Director of District 9", a hot young A-lister in the Newt role, building off the two beloved entries? Are you kidding me? Gangbusters.
Similar reasons as to why Alien: Covenant will do so well. The trailers are going to sell it for what it is: the return of the classic Alien life cycle, "From the Director of Alien and The Martian", beloved David character returning x2, using the Alien name. Gangbusters. Fox's lofty investment will be rewarded I feel, despite the movie being called "dark", "bleak" and "macabre" by the cast and crew.