if you are pretty certain your yeast can be stopped with cold temps then there's no reason you can't do what you suggest, just by racking to a keg and getting it very cold very quickly. when i make semi-sweet cider i do a hybrid between what you suggest and what yooper suggests above. i ferment dry then backsweeten, keg, force carb, bottle (beergun) and then pasteurize. this tends to go very well since the bottles don't have the high pressure experienced during bottle carbing, so they don't explode as readily. unless you leave them around a while between bottling and pasteurizing, then you're asking for trouble. i leave mine overnight to warm up since they are force carbed cold. i have never cold crashed during fermentation, i like to leave them to finish completely, rack once, let them drop completely clear in secondary, then keg and sweeten. this way you don't need sorbate or extra sulfite (you may want to use a tiny bit of sulfite for its antioxidant properties, but if you're drinking it quickly i'd skip it). i can only attest to this working with s04 and s05 ale yeasts, and to it decidedly not working with a wild fermentation.