¡Muy bueno! I like your translations, perfect. Many of the Spanish words would not be familiar to the Spaniards any more, ‘garridas’, ‘desmaídas’. Most Spaniards will understand a very sexual subtext in
Tres morillas tan garridas
iban a coger olivas,
y hallábanse cogidas en Jaén
‘Coger, cogidas’ in many Spanish speaking countries, hmm, it is a verb forbidden to use in polite society, if you get what I mean.
The version that I learn in school (!) said
‘e fallábanlas cogidas
With its emphasis on the olives and not on the three girls it is a lot more tame.