The third result that has a Chinese site mentioning the year 1588 is in reference to when the Qianfodian (Thousand Buddha Hall) was constructed, the one with the impressions in the floor from Xinyiba training. That article also concludes that Xinyiba was from the early stage of development, when Ji Jike was at Shaolin, prior to Xinyi Liuhequan.
This also makes sense, as Ruan village which separated from Shaolin roughly 360 years ago (around the time of the massacre) also had/has some Xinyiba. If Xinyiba came from Ji Jike's later material, introduced to Shaolin the 1700's, as opposed to coming out of his early teachings between the 1620's and 30's, Ruan village shouldn't have received it.
It would appear Ji's early material became Xinyiba in Shaolin's Nanyuan (which Ruan village came from) and Xinyiquan sets of the Changhuxinyimen sect of Li Jiyu who mixed his Mogou village style with Shaolin Monastery's Nanyuan and Ji Jike's new concepts.
That being the case, what Li Shiming passed to the abbot in the 1700's, "12 Moves of the Xinyi Liuhe", taken in as Xinyiba, was a different type of Xinyiba than what came out of Ji Jike's early teachings.