You answered my initial question stating that the geometric relationships exhibited between G1 and G3 was probably coincidence and then when I subsequently asked you to quantify your probability, you then claimed you had "no idea".
Well ... according to Lehner:
... the 4th Dynasty builders took pains to ensure that major parts of the pyramid complexes would align. (Complete Pyramids, pg 106)
Surely the inevitable conclusion, therefore, is that geometric relationships between the pyramids, far from being coincidental, would themselves be inevitable.