You are crazy if you think you will ever get one of those to fruit in your climate. Seedling durian trees are often 30+ feet tall when they fruit for the first time. By no means are durio seedlings dwarf. However, I have seen grafted, dwarf-like trees in the Philippines that would fruit, one particular tree that was about 8 feet tall and was in a large fabric pot. The people were able to select this dwarf-like tree out of a nursery of 100s of grafted plants. If you had this option to import grafted , dwarf varieties then maybe someone could get it to fruit in a temperate zone greenhouse , but a seedling ? No way