From pp25 of the condensed biography of Sri Ramakrishna "A short life of Sri Ramakrishna":
As it is not considered advisable to undertake the worship of Shakti,
or Kali, without being properly initiated, Sri Ramakrishna, at the
advice of his elder brother, got the necessary initiation from a
Brahmin in Calcutta named Kenaram Bhattacharya who was noted for his
devotion and experience. It is said that as soon as the sacred Mantra
was uttered in his ears, Sri Ramakrishna, overwhelmed with religious
fervour, gave a shout and plunged into deep concentration, which
greatly astonished the Guru.
This happened after Sri Ramakrishna was appointed as a priest of the Kali Temple. I don't know anything about the higher Gurus of this lineage though.
But, Sri Bhairavi, the Tantrik female-Guru of Sri Ramakrishna, initiated him into Vishnukranta Tantras (i have read this in a Bengali biography of Sri Ramakrishna), which are Shakta Tantras.
It is said that, under her guidance, he practiced the 64 Vishnukranta Tantras. (Not sure, though, what it means by saying "practicing 64 Tantras" probably the meaning is- practicing all the principle Mantras contained in each of the Tantras?). So, Sri Bhairavi may well have been his 2nd Shakta Guru.