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Interestingly Rigano, Pyramids of the Giza Plateau p77-81, argues GI-d and GII-a, Khafre's satellite pyramid, to be contemporary.

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As much as GI-a, b, and c are alike, the recently discovered GI-d is clearly different....

While the general belief among Egyptologists is that GI-d was a planned part of Khufu's Mortuary Complex and possibly served as his ritual pyramid, the facts argue against this belief. Its size at only 10% the volume of the other subsidiary pyramids and its "T" shaped substructure clearly sets GI-d apart from the other three subsidiaries but bears a strong resemblance in size and internal layout to GII-a, the minor pyramid to the south of Khafre's pyramid...

It is very unlikely GI-d was built first [before the enclosure wall and associated mastabas] and defined the locations for the outer enclosure wall and mastabas. It is much more likely the boundaries were there first and defined the space and size of a pyrmaid built after all were in place. This sets the earliest possible construction date for G1-d to after completion of the southern mastabas. The timing makes GI-d and Khafre's subsidiary pyramid (GII-a) contemporary and explains the similarities between the two pyramids.