I have been reviewing the gravestone from the Ancient Prague Cemetery, as edited by Otto Muneles in 1988 book. The grave of Akiva's daughter Yocheved Horowitz is there. Here is what Muneles comments regarding the family of Akiva (roughly translated):
"...nothing is known about these people [referring to Akiva's ancestry] in the 15th century, but only in the 17th century..."
Muneles then goes on to report several entries from the books of the Prague City Council:
"Yosef, the brother of Kiba (Akiva), bought in 1523 (ibid., page 211b) for himself and his wife Fromet half a house in the amount of 10 sheqr fr. It seems that in 1532 Yosef got involved in the bankruptcy of the heirs of Meir Horowitz (2111, page 17); In 1533 (ibid., page 57b) Yosef Valach, he and his wife Pyaarle, bought a house from Yosef, Akiva's brother, in the amount of 104 sheqr ch."
SOURCE: Epitaphs from the Ancient Jewish Cemetery of Prague, Edited by Otto Muneles, Israel Academy of Sciences and Humanities, Jerusalem, 1988, p. 166 (65).
Meanwhile, Jacobi worked on the Akiba tree, but his work was not finished and there is no HaKohen "A" (as he called this line) in the published Jacobi Papers. There is some partially finished work on the Akiva tree in the unpublished Akiva papers housed in the Paul Jacobi Collection in the National Library of Israel (Givat Ram Campus of Hebrew University).
However, it is possible to reconstruct some Jacobi's work on the Akiva tree in the published papers, because of references in the published chapters to the HaKohen "A" line. I have made a gedcom file showing what Jacobi did with this family, which is quite interesting. I cannot upload this to GENI because the profiles are form before 1800 so I an can only offer a download of the gedcom for those interested: https://1drv.ms/u/s!AuwT-4qnkJLBoSfI97bZGIDCqWyb?e=qIUDlE.
So it seems that neither Muneles nor Jacobi found any evidence connecting HaGaon Rabbi Akiva HaCohen Katz, of Ofen to Rabbi Yitzhak HaCohen Katz, [of Galata] or Rabbi Akiva Hakohen Katz, ABD Saloniki (Alter of Salonika)
