Hi Michael, a couple of corrections to your pdf...

There were actually three films tested, you didn't mention the Plus-X Pan. And their gamma aim was actually 0.65, not "~0.63), as I quoted in post#9.

And a general note to all readers: I call the developing agent "Elon," per the original paper, which also says "*Kodak's Elon Developing Agent is the Eastman Kodak Company trade name for p-methylaminophenol sulfate." But apparently Metol is the generic trade name for the same thing.

Here's your question list and some answers (I didn't proof-read carefully, so may be errors; if anything looks funny, please ask):

Some methodology questions:

Q1. Were pH figures presented in the original paper?

A. No. Here's a more complete excerpt from Altman and Henn:

Developer Formulas. The first step in the experiment was to formulate the appropriate series of developers. This was done by the sensitometric testing of preliminary formulas with the aim of establishing reasonably uniform activity levels and development times. The first section of Table I shows the composition of the fine-grain series (Series I).

The central formula in this series, AH-3, is essentially Kodak Developer D-25. It is a true fine-grain developer, giving grain reduction at the expense of reduced emulsion speed. The solvent actin has been lowered in the AH-1 and AH-2 formulas by decreasing the sulfite content. Since this reduction would lower the pH and the activity as well, most of the bisulfite was removed in AH-2 and Kodak Balanced Alkali was added in AH-1. Formula AH-4 contains more than the usual amount of bisulfite. This maintenance of approximately constant activity was considered essential since Henn and Crabtree (J. Photo. Soc. Am.,1: 727 (1944)) have shown that graininess is affected by both activity and sulfite contents.

The solvent action is obtained from the combined effect of the sulfite and bisulfite, and these are totaled as moles of sulfite ion in the table.
*Rather than type the full text of the high-sharpness section, here is a pertinent bit (re: AH-15 through 18):

They all contain 10 grams of sodium sulfite per liter and the proper amount of alkali to equalise the activity. Full compensation of activity was not possible in the case of AH-18, containing the least amount of Elon, but the others are matched reasonably well.
Q2. Why was a buffering alkali used particularly for the sharpness developers?

A. I don't know, other than what is in the quotes above.

Q3. Was agitation consistent for all tests?

A. All that is said is:
Processing was in the sensitometric machine of Jones, Russell, and Beacham (Jour. SMPE, 28:73 (1937) which gives strong and uniform agitation.
Q4. Was D-76 used at stock or 1+1 strength in the Tri-X test?

A. The table for Tri-X simply lists "Kodak Developer D-76 (footnoted "average of 2 runs"). So one has to consider it to be straight D-76. I don't know why they would change dilutions on this one (the other two films were both noted as "1:1"), but the actual development time they used is consistent with 1970's era development times in straight D76. So I would consider it to be straight D-76.

Q5. Why would the developing time for AH-15 be longer shorter than for AH-1 if the only difference between the two developers is a lower Metol concentration?

A. I don't have a sensible answer. It's worth noting, though, that they attempted to develop to the same gamma - their developing times originated from prior time-gamma studies. I'll look the data over a bit more.