(a) It is twelve noon, Sunday, Jan 3. VOA Chinese has not reported the disappearance of .李波.
(b)
(i) Although this BBC report has a photo atop, whose legend states, "何俊仁（中）表示据传巨流传媒被劝止不要出版有关 '习近平情人' 的新书," the report does not say when the photo was taken and for what purpose.
(ii) This BBC report does say, "香港市民支持爱国民主运动联合会（支联会）主席何俊仁周日（1月3日）称，这本书据信是有关习近平年轻时的情人。* * * 何俊仁在新闻发布会上说 * * * "
The report does not explicitly say the press conference was held on Jan 3, and I did not know it after reading it. However, it is true that 何俊仁 held a press conference on Jan 3 and made those statements there. See (2).
(c) Only BBC (as well as those agitators in Hong Kong) mentions the book in the making, and as a potential motive of the series of disappearances. Not (2) or (3) below, and certainly not Hong Kong government.