Re: Can planets in Fall or Detriment be perigrine?
Ptolemy makes no mention of the peregrine state either in the "Tetrabiblos" nor in the "Almagest".
Reference to peregrine as being devoid of dignity AND debility/detriment, is found in Abu Mashar's "Great Introduction" (and, I think also in the "Abbreviation"), in Paulus Alexandrianus, in Maximus (late Classical-era authors), and in Thabit ibn Qurra's "Ghayat el-Kawakeb' ("Way or Path of the Planets")
I seem to remember (but would have to check specifically) peregrine is also defined in this way in Valen's "Anthology" and (perhaps) in Maternus "Mathesis".
Al-Biruni ("Book of Instruction"), c 1058 AD, seems to give a definition of peregrine somewhat more in line with the later definitional framework of that state:
(pg. 82) "...if, however, it is not in a favorable situation, it is said to be "peregrine", while if either in its detriment or its fall. calamity is added to the alien situation."
Here, Al-Biruni seems to hold that the peregrine state (as just being devoid of dignities) is rather neutral, but coupled with also having detriment or fall, it is very disruptive/harmful to the influence of the planet: this is definitely a different attitude regarding peregrine than that held by later authors, who consider the state itself (just being devoid of dignities) as quite negative.
Manly P. Hall (20th century) makes reference to (unspecified) early authors who defined peregrine as "without essential dignity OR debility/detriment", and Modernist Charles Carter makes a similar historical definition of this term (Note: the peregrine state is not recognized in Modernist astrology)