I actually tried searching in Persian for a Chinese place in Mashhad, and I think I may have found the only one: Marina Restaurant. This may be the same place as in this picture because it appears to be an Eastern Asian place that does Japanese and Chinese. (The picture is of a westernized Japanese teppan-yaki.)
Pyongyang most definitely has Chinese restaurants. Pyongyang isn’t like the rest of NK. There’s enough of a (relatively) wealthy elite that you will find several restaurants offering anything from lots and lots of Korean to sushi, pizza, Chinese, micro-breweries and even hamburgers.
Chinese food can be swimming in grease, though I think it’s more a matter of how the grease is presented rather than the actual amount of grease. In Western food, we are used to the grease being incorporated into the product- fats are incorporated into batters, baked goods, and sauces. In Chinese food, it’s mostly outside of the food, so the food appears to be sitting in a pool of oil. But in the end, I think it works out to being pretty much the same amount.
As for sweet, I haven’t encountered a lot of sweet Chinese food. I lived in Sichuan where the food was extremely spicy and incorporated a special type of pepper that creates a numbing sensation, so that was what most of the food tasted like. Other areas may be sweeter, but I don’t think they get as sweet as American Chinese food.
Ate Chinese food in Cairo. It was very much like one would eat at a mall in the US. It was delivery so I couldn’t tell you who was in the kitchen. No pork on the menu.