Meir Pochachevsky (Lipschutz) - Meir Pochachevsky - probably not from Danzig

In looking for the source of Rosenstein's claim that Meir Pochachevsky came from Danzig and was known as Meir Danziger, I found it to be a direct quote from Tidhar, D. (1949), which has the identical information. Entsiklopedyah le-halutse ha-yishuv u-vonav (Vol. 3, p. 1281); that entry is not sourced. Retrieved from http://www.tidhar.tourolib.org/tidhar/view/3/1281.

According to available information and this Geni tree, Yehiel Mikhel Zalmon Pochachevsky was Meir's son. A memoir by Yehiel is in the Brest Yizkor book (https://www.jewishgen.org/yizkor/Brest2/bre211.html). The memoir makes clear that his paternal grandfather, Meir's father, was an established factory owner in Brest. If Yehiel's grandfather was already established in Brest, then it is very unlikely that Yehiel's father, Meir, came to Brest as a merchant from Danzig.

Yisrael Lipschutz was the rabbi in Danzig, but I am still looking for any documentation of the generations between Yisrael Lipschutz and Meir Pohachevsky or his father, who is theoretically my 3great-grandfather.