As has been covered many times before on this forum, the torque values stamped on stems, bars and other parts are NOT recommended torque, they are the MAX torque. The REQUIRED torque is the amount that is necessary to firmly hold the part in place. For example, most 4-bolt stem plates only require 4-4.5 Nm of torque to firmly hold bars in place, not the 5 Nm or 8 Nm that u often see stamped as the MAX torque value.
This is absolutely correct, and that is exactly the purpose of carbon assembly paste; to reduce the torque required to get the part to hold properly, guaranteeing you will not even approach the maximum torque of the part in question.
As for lube - the interference face of any bolt should be dry, but the threads should have anti-seize paste or grease on them. This is not so much a lubrication issue as it is one of dissimilar metals in contact with one another. The grease or paste will ensure that you can remove the bolt much later without breaking it. Automobile wheel bots rely on a slight deformation of the soft bolt shoulder when torqued properly, and should never be lubricated. Other bolts are selected for head type, etc., based on their proposed usage and torque requirements. The variance in stress when torqued to spec WITH lube on the heads from one bolt to another can be quite large, due to the variance in the type of lube used and application.
Bottom line - use a torque wrench, do not lube the heads of the bolts, DO use carbon assembly paste, and torque all bolts progressively to the same torque, which will be considerably less than the max. torque specified on the part if you use the assembly paste.