I am interested in any and all details you can possibly give me. Ceremonies, materials or religious texts related to both gods, everything. I'm specially interested in Edfu's Horus (even more specially in Apollonos Superioris ptolemaic Horus) and Avaris's Seth, in case there is anything specific to them.
This is a huge question to answer. The most comprehensive source for academic citations on Ancient Egyptian material, the "Online Egyptological Bibliography," lists 2384 academic sources with Horus as a component of the source, with a further 871 dealing with Seth. Therefore a comprehensive answer about what we know about Horus and Seth would be far beyond the scope of this format. What you are probably better off looking for are some accessible sources on these gods. The standard books for Egyptian deities are Geraldine Pinch's "Egyptian Mythology: A Guide to the Gods, Goddesses, and Traditions of Ancient Egypt" and Richard Wilkinson's "The Complete Gods and Goddesses of Ancient Egypt."
As far as primary sources specifically about Horus of Edfu, I would recommend looking into "the Myth of Horus at Edfu" which is published in issues 21, 28, 29 and 30 of the Journal of Egyptian Archaology. There is also another published ceremony called the "Hwt bHsw" related to Horus of Edfu which is published in issues 35 and 36 of the Journal of Egyptian Archaology. (Here is a JSTOR link to the journal https://www.jstor.org/journal/jegyparch)
As for Seth of Avaris, the only source I can find in English language is Labib Habachi's article from 1974 "Sethos I's devotion to Seth and Avaris."
Your best source for both of them in general is going to be "The Contentendings of Horus and Seth" for which the standard translation by William Kelly Simpson can be found here. http://www.reshafim.org.il/ad/egypt/texts/horus_and_seth.htm
Hope this helps.