If you go with pastuerized (heat sterilized) but preservative free apple cider you won't have to boil it. All the bugs in it are dead.
Also, you can dissolve the brown sugar in a 2-3 qaurts of you apple juice over heat, and leave out the 1/2gal of water.
I don't have a mental picture of the spice blend. I would be inclined to leave all the spices out (lemon, oak, cardamom) until primary was complete, then add the spices (without even racking) and leave it to bulk age on the yeast cake until the spiciness was about right. Then bottle.
Is the 3/4 cup corn sugar for priming/bottling?
If you have tried that recipe and the brewer gave you the recipe, great. Otherwise I would suggest a scaled down 2-3 gallon test batch.
I have never made a cider that reached its peak in under 6 months, and those are limited to graff style iders with a bunch of yeast nutrient in the barley portion.
If you do make it don't dump it out until it has been cellared at least one year.
Don't let me talk you out of it, it might be great.