1. Micheli is not Mignini.
2. "rito/i" means a lot of things. It's a more comon word in Italian than English, used to mean more things than the English "rite"/"ritual".
It means "rite", but it also means "procedure" or "practice". For example: the abbreviated trial, like the Guede trial presieded over by Micheli, is called in Italian "rito abbreviato". (sc MOTIVATIONS quoting Hellmann: "dal momento che il giudizio che ha riguardato il Guede e stato celebrato con il rito abbreviato") (obviously here you would translate "rito" with ="procedure").
You find the word again at p. 59:
"Non può portare ad opinare diversamente il fatto che le violazioni al codice di
rito pacificamente consumate (per stessa ammissione della difesa Sollecito) sarebbero incorse su impulso del rappresentante della pubblica accusa".
If you refer to customs, things usually done or repeated, the translation may be "practice", or the expression is translated with an adjective (such as "usual", or "required", or "due" etc.). On a birthady you may say "auguri di rito" (the usual/due birthday wishes); when you meet a person "saluti/conversazioni di rito" (the usual/due greetings/conversation); "frasi di rito"= "common phrases"; "documenti di rito" would be "required documents".
Outside colloqualism, rito/i is still rather common; for example the Tango (a dance) due to its precise style can be referred to as rito as in this book
http://www.ibs.it/code/9788888475387/de-marchi-lucia/tango-venezia-espressioni.html.
Or intended as just "custom", "traditional habit", "practice", it may be just used to address parts of the culture life such as eating food, like in this book:
http://sellerio.it/it/catalogo/Cibo-Rito-Gesto-Parola-Alimentazione-Tradizionale/Grimaldi/5260 .
Can be referred to holidays. Children holidays at the seaside is called "rito" fby this newspaper:
http://www.ilgiornale.it/news/interni/e-i-bambini-dellera-internet-torna-rito-delle-vacanze-941236.html; it means obviously a precise "habit". A usual holiday habit "interrupted", is described by this article:
http://corrieredelveneto.corriere.it/veneto/notizie/cronaca/2013/31-agosto-2013/vacanze-estive-la-madre-rito-interrotto-la-nomina-2222846203627.shtml.
This mother writing on a forum calls parenting techniques are "riti": (repeated actions, habitual events)
http://www.nostrofiglio.it/forum/nanna-106/rito-della-nanna-vacanza-15090/
A habit to make your child sleep: rito della buonanotte (good night practice):
http://www.momentimagici.com/consigli/sonno-32/i_primi_sogni-65/il_rito_della_buonanotte.-67.html
Anyway, the meaning of "rito" has the same semantic basis of the English word so the nucleus of its use is similar, the whole use is a bit wider but the word is similar.
Magic/Pagan rites and rituals - that may be partly superimposed to the concept of "holiday" - do exist in Italy. This article for example, tends to use the word meaning both the holiday event and the magical rituals through the town (Nights of Magic, in a Southern Italian village)
http://www.basilicatavacanze.com/riti-e-spiritualita-nelle-notti-della-magia-ad-albano-di-lucania-pz/
This is what the word means, but pay attention, Mignini doesn't use it.
I read elsewhere reported that Mignini (maybe in a court reply) also defined the "festino" as "rito casalingo" (house-made-rite), but this is was reported within inverted commas and it is almost an oximore ("rito" and "casalingo" tend to be opposites, "rito" meaning precise, due, exact, predictable and some established practice; "casalingo" meaning imprecise, gross, casual, clumsy and impractical, non-established and house-made).
This is the only context in which the Italian press reported the word "rito" as being used by the prosecution (that would be, obvious, a slightly ironical context), however I never found this word in the trial papers.