While it's true that there might be some reason to guess at a Vedic influence on Plotinus, the thread from Plotinus to Kabbalah is long, indirect, and vague. Even if proved true, that would make the influence third- or fourth-hand at best, which to my mind isn't enough to claim a direct relationship, let alone a causal link.
As for Philo, though he certainly was a neo-Platonist, I doubt his influence on Kabbalah. He lived in a Hellenistic community far removed from the centers of early Jewish mystical thought, and his work was little studied in mainstream Jewish communities until many, many centuries later-- even then, he was seldom of great influence, since other, more respected authorities had made many of his key points on their own.
The initial Platonic influences on early Jewish mysticism seem to have come from Hellenic syncretism (greatly modified) in the time of the early Rabbis of the Talmud (first couple of centuries CE); the neo-Platonic influences may possibly be visible in some of the more mystical passages in the Gemara (the later portion of the Talmud), but it's debatable. The certain neo-Platonic influences came during the time of the Gaonim (6th to 11th centuries CE), especially in the time of Rav Saadiah Gaon (882-942 CE). Rav Saadiah was deeply influenced by neo-Platonic thought, especially as filtered through the Muslim philosophers of the Mutakalimi and Mutazili schools of thought.