The Manimekalai is a 6th century Tamil epic poem composed by the Buddhist poet Chithalai Chathanar. It talks about philosophy a lot, which given its early date means that it gives a rare glimpse into what the Vedanta school was like before the time of Adi Shankaracharya. In any case, in this chapter of Manimekalai, various Pramanas or means of valid knowledge are discussed:
Discoursing on the instruments of knowledge as recognized by his school, he pointed out that three teachers were recognized as of authority among them, namely, Vedavyasa, Kritakoti and the faultless Jaimini. These three have recognized instruments of knowledge to be ten, eight and six respectively. Those are (1) direct perception (Pratyaksha), (2) Inference (Anumana), (3) similitude (Upama), (4) authority (Agama), (5) inferential assumption (Atthapatti), (6) appropriateness (Iyalbu or Svabhava), (7) tradition (Aitihya), (8) non-existence or negation (Abhava), (9) inference by elimination or by correlation (Mitchi or Olibu, Sans.: Parishesha) and (10) occurence (Undaneri or Ullaneri, San. Sambhava).
I'm interested in the part in bold. Two of these names are easily recognizable: there's the sage Vyasa who founded the Vedanta school, and the sage Jaimini who founded the Purva Mimamsa school. Kritakoti isn't as familiar, but I think it refers to the sage Baudhayana, who wrote a commentary on the Purva Mimamsa Sutras and Brahma Sutras called Kritakoti, as described in this quote from a Purva Mimamsa work called the Prapancha Hridaya:
The Mimamsa Shastra is contained in a text of 20 chapters. Of these, the first 16 chapters constitute the Purva Mimamsa. In this Mimamsa Shastra, the Purvakanda deals on issues of Dharma, and is compiled by Jaimini. The last 4 chapters constitute the Uttara Kanda or the Uttara Mimamsa and are compiled by Vyasa for dealing with the nature of Brahman. On this Mimamsa Shastra of 20 chapters, Bodhayana wrote a Bhashya that bore the name Krtakoti.
Now it makes sense that the Manimekalai would say Jaimini believed in 6 Pramanas; that's at least the number of Pramanas accepted by the Purva Mimamsa philosopher Kumarila Bhatta. But it's strange that it would say that Vyasa believed in 10 Pramanas and Baudhayana believed in 8 Pramanas. No existing Vedantic philosophy believe in that many Pramanas; as I discuss in this answer, Advaitins believe in 6 Pramanas, and all other members of the Vedanta school believe in 3 Pramanas.
So my question is, is it true that Vyasa and Baudhayana believed in 10 Pramanas and 8 Pramanas respectively? As I said, the Manimekalai was composed by a Buddhist, so it may contain some inaccurate information concerning Hindu beliefs.