How Much Torah Did Avraham Avinu Keep?

There was recent discussion on Avodah about how much Torah Avraham Avinu and the Avot kept.

The question posed to the group:

: Obviously the sheva mitzvos b'nei Noach they observed but how did
: they know about the chukim and korbonos, as well as tzitzis, mezuzah,
: tefillin, etc. etc. etc.?

An answer given by the moderator:

(Mefarshim on the chumash generally address this on Bereishis 26:5.)
Rashi says they kept all the mitzvos. But if you turn to the gemara
Yuma 128b, there are three opinions.

1- Rav: The avos keps the entire Torah
2- R' Ashi: ... even the derabbanans.
3- R Shimi bar Chiya: Avraham only kept the 7 mitzvos and beris Milah.

(If we're talking all three Avos, presumably the only variation is
Yaaqov and his sons keeping gid hanasheh.)

Rashi is quoting Rav Ashi. But he is in the minority. Most rishonim hold
like RSBC. Including: the Rambam (Melachim 9:1), his son, the Me'iri
(intro to Avos), the Ramban, Seforno, IE, Radaq, Chizquni and the Ramah
(okay, not a rishon).

According to RMMS's understanding of RYYS (Sefer haMaamarim 5697, pg 282
in a hagah titled "beruchnius velo begashmius), Rav and R' Ashi aren't
being fully literal. The avos accomplished the spiritual objectives of
the mitzvos, and not for every mitzvah did they physically fulfill it
as we would.

RCVolozhiner holds like Rashi, and answers your question in NhC 1:21. He
holds that they were aware enough of their souls to detect what was
missing and intuit halakah.

I will add that one Kabbalistic approach to this goes even further than Rav Ashi. According to Ribbi Yaakov Abuhatzeira ZT"L in Mahsof Halavan, Avraham Avinu even kept Tikkun 4 Olamot of Shaharit based on the writings of the Ariza"l.  "And it's not Shayach - has veshalom - that anything - big or small - would be hidden from him as he was a Merkava for the Shechina and the beginning of the structure of holiness and the world existed only upon him..."