Thanks for all of your help! I'm glad that it seems like we're getting closer to the root of the problem
Here is a partial set of results.
1. Voltage with everything off: 13.37, 13.36, 13.36 (fully charged); after cranking, this resting voltage dropped to 12.5 and 12.47
2. Voltage while cranking: 11.5, 11.6, max = 11.64
3. Can you clarify what you mean by this, please? Does this mean I should get the voltage from just one terminal of the battery? If so, where do I place the other lead to close the circuit? Where do I find the coils' red terminal?
4. There is a bright white/blue spark on both spark plugs while cranking and grounding the plugs to the engine. Very consistent results/spark.
5. TBD - going to get a beaker first. Also...
6. Before putting the fuel tank back on for #5, can you clarify this test, please? What am I isolating from one another? In other words, what should I be leaving on the bike/connected vs. what should be taken off? Is the "fuel-delivery" you're referring to just the hose connecting the petcock to the carbs that delivers the fuel (not the vacuum hose)? Just wanting to make sure I do this test correctly.
I did get a new battery last year, and that seemed to be one of the major causes of the bike to start again last year. Not sure how it's held up since, but it's seen very little use since being replaced.
Additionally, I redid the dry compression test with both spark plugs off. Results were consistent with the previous test (left = 70 psi, 70 psi; right = 72 psi, 72 psi).
I also have not formally verified that the cam timing was correct (I wasn't directly looking for it while doing my valve adjustments), but nothing looked out of the ordinary when aligning the valves to TDC.