Barath, about your queries about which ingas do best in cooler climates, you need to look for ingas originationg in southernmost Brazil, Argentina, Uruguay, Paraguay. There are plenty of these as there are between 250-300 species, depending on which author you consult. You can see the origin of each species in a book that is a monograph on Ingas by T. Pennington.
As a tangent, it's interesting to note that the inga genus has more species in danger of extinction than almost any other tropical fruit.