Does character level determine level of items crafted from legendary/set plans?

Solution 1:

Character level does not influence the level of dropped plans, it might influence what plans drop, but a plan for archon spaulders of strength is always going to be a level 60 item. This goes for all dropped recipes. If the resulting item is a Legendary, a set (basically a subclass from legendaries) or a rare doesn't matter.

The crafted items will also always be crafted at the same level regardless of what level the character crafting them is. A lvl 1 character can craft lvl 70 items.

Solution 2:

Nope, character level means nothing at all. Each crafted item has a required level to be used, and it will roll from those affix pools at the time of creation.

You can generally tell around what level the plan will be, by checking the required blacksmith level. A level 10 plan requires level 60, and level 12 plans require level 70.