What LNAB to use for Rodrigo, Count of Castile?

Question

Rodrigo, the first Count of Castile (conde de Castilla in Spanish) in about 860-873, has at least 4 and possibly 5 or 6 profiles on WikiTree that need to be merged.  The difficulty is that in early medieval sources, his family name or parents are never stated, and although there have been theories over the years, none of them have any major support, and several are definitely incorrect.  See the brief discussion by Charles Cawley about this issue.

The other issue is that all the profiles have a different Last Name at Birth (LNAB) and the question is to select an existing one or change one to something else?

Although technically the Last Name at Birth (LNAB) of Castilla is incorrect because he wouldn't have been appointed as Count of Castile until he was an adult it may be the best option in terms of how the profile is named in other sources.

The other option is to change the LNAB of one of the profiles to Unknown, and then use 'de Castilla' as the Current Last Name.

Other profiles

Rodrigo de Castilla, LNAB Asturias-47
Rodrigo Bermudes-20
Rodrigo Castilla, LNAB De Castilla-48
Maybe
Rodrigo I Frolaz Castilla, LNAB De CASTILE-16
Rodrigo Frolaz-1

(Note - it is best to decide on the LNAB and then merge all profiles into that one, rather than merge them and decide on correct LNAB later - see multiple redirects problem)

Answer 1

Bermudes/Bermudez that's used on one profile is a patronymic, not a surname, and anyway it's a-historical since we don't know for sure who Rodrigo's father even was.

Without any real confirmation of his origins, Unknown seems the best option.

Answer 2

While it is WikiTree policy to use "Unknown" as a LNAB when the parentage is uncertain, there is precedent for alternatives with Medieval profiles.  An example would be the early generations of a family dynasty or house, where WikiTree may assign them a single LNAB (such as Bosonid).

Rodrigo was the first named Count of Castile (Conde en Castilla).  Since he is most commonly known as such, I think Castilla would be an acceptable choice.