The interesting thing is Ridley being taken by the idea enough to re-approach Alvarez some years after his original pitch.
Considering Ridley keeps saying the beast is cooked, there must be some element that could connect to the prequels, and it wouldnt suprise me if Alvarez reworked some elements to ensure he got the gig.
Im sure it will be standalone, but perhaps some subtle connections. Engineer ruins seems plausible enough.
I just hope they go back to basics in the approach and please restore all the biomechanoid elements.
I can't wait for this.