I play various string instruments including the classical guitar. I retired from the New York Times where I was employed as a staff news photographer from 1969 to 2001. I am presently the director of the Puerto Rican Cuatro Project with co-founder William Cumpiano (book: Guitar-making) , finishing a book on the spanish string varients that developed in Puerto Rico after 1512.
I think I would be a bit cautious about saying that the Puerto Rican vihuela was directly influenced by the baroque guitar. One thing about it that seems to me unusual is the single 5th string - is there any practical reason for this? Apart from that - re-entrant tunings are usually adopted for convenience - either because of problems with the kind of strings available or because it is easier to arrange the music on the fingerboard. If the instrument just plays the meolodic line there are advantages to re-entrant tunings especially if the instrument is played with a plectrum. It is a difficult question to give a definite answer to!