Sharq, Yes, I agree that it doesn't look like any longan trees I have growing in my yard. I have many seedlings and large trees and the leaves look like what you showed above.
But when I go to this person's house to graft other fruit trees, she insists it was a longan fruit she ate years ago, then planted the seed and this is the tree.
Shot, does a Ficus have fruits, she insists it was a good tasting fruit. I believe her since she has over 5 excellent seedling fruit trees grown in her yard. I dug up her 16 ft white sapote seedling tree which gives good fruits. She has been planting seeds from the best tasting fruits for over 15 yrs now. One other excellent seedling is her Kumquat tree which gives large Nagami size fruits, but tastes better, some people tell me they thought the fruits tasted like a mix of Nagami and Meiwa when I asked them to try the fruits.