We do not know which of the sons of Amador de Lousada became known as Isaac. Perhaps is was Pedro born around 1586 which is the date we show.
The first-born son of Aaron #376 was named David and not Isaac which was the name given to the 2nd son who was born on 23 Tisri 5440 but died on his 7th day! This presumably means that the natural father of Aaron was David an earlier husband of Luna. Of him we cannot say much - other than that the 2 husbands may have been brothers. In this case, the hypothetical earlier David may have been the grandfather of the first David of Surinam! That is Luna had a son Moses with David as well as a son Aaron.
Note that the first son of David #44 was named Isaac in accordance with the normal rule but David was younger than Aaron and therefore Isaac #42 was the natural father.
Isaac's wife and a daughter were both named Luna - meaning that the name of a grandmother was Luna also. Gracia was probably an earlier daughter than Luna, but perhaps the natural paternal grandmother was named Ana so perhaps an even earlier daughter died.
burial record http://www.dutchjewry.org/P.I.G./image/00252001.jpg