Probably and survive 9 out of 10 years if properly root pruned. For insurance I always bury the smaller pots (I have a few and one northern italian fig from a friend in ground) in my empty vegetable bed during winter and pop a garbage pail over it. One big one (Greek Fig) in a pot is too big too bury so I throw a frost cloth over it. Momma fig is still alive at my friends family house in Greece and a 3 story clone exists at his Brooklyn House.

This particular seed grown Citrangequat (from woodlanders) is entirely trifoliate leaved, it survived not one but two separate winters planted directly in my garden with different kinds of passive protection. I pulled it to recoup in a pot. It is destined to be outside permanently at some point. I have a much smaller grafted unifoliate version from McKenzie fruiting now

I've heard most people aren't big fans of sunquat. Kumquats are supposed to be eaten for their exterior peel, and Satsuma mandarins for their delicious inside, but I guess these two different traits don't combine together well. They are supposed to be pretty cold hardy though. Kumquats and Satsuma mandarins are the hardiest of the ordinary citrus you will ever find in a supermarket. They can be grown in zone 8a in the South. Maybe even just a little colder if planted up against a house in a warm spot.

That's not uncommon. It means the tree doesn't have enough energy or vigor to sustain fruits yet. When the tree gets bigger in a few years you should have more luck.