Update: Fruit fully ripen today and I was able to confirm that its an Annona Montana, aka Mountain Soursop.
Taste is not the best, but I am making the best of the fruit in two ways. One is for a 'smoothie' like drink, and second i'll be using the seeds to grow as root stock for other compatible annonas.
Willing to experiment a bit with this one, ultimately want to graft some cherimoya varieties to see if I can get some fruits in South Florida.