I've been engaged in a detailed analysis of current consumption by various ternary gates in different configurations so as to better understand why the Sum gate was drawing so much current. I've concluded that by drawing more current than the wall wart could supply it became damaged which resulted in the crazy measurements I was getting right before it died permanently.

Since then I've been studying how much current is drawn by different configurations of the ternary gates such as with different pull-up, or pull-middle resistors, different resistors on the input pins, terminating or not terminating unused comparators on an IC and so forth. Over 160 individual measurements so far. The conclusion I'm coming to so far is that I should have been using larger resistors for my pull-ups and pull-middles, and that I should not have been neglecting resistors on the comparator inputs. The LM393 comparators and discrete transistors don't have any difference in current draw by adding input resistors, but the LM319's have a significant difference. This doesn't fully explain how I was drawing over 200 mA with just six components and no short circuits, but I'll just have to build up the Sum gate again, keeping track of current consumption as I power and connect each device.