1. On two occasions (that I can identify), Dempsey instructs the reader not to move his feet: (a) whilst executing the rudimentary shoulder whirl movement—with feet parallel—and (b) whilst executing the movements of the shovel hook.

Pivot, just do not step....at least that is how I see it.

2.Why, do you think, does Dempsey teach the initial movements of the
shovel hook from the "normal position" and not from the feet-parallel
position, as he does with the whirl straight punches, outside hooks and
uppercuts?

Not sure why he does this, I don't teach the shovel hook from a parallel position either.

3. The concept of the power line still eludes me a bit.
In describing the movements of the left jolt, Dempsey says to shoot the fist along the power line. Is that simply his manner of saying, shoot from the shoulder?
It would seem to me that the power line would vary depending upon the location of the target, and thus it could become rather difficult to follow the power under certain circumstances.

For example, if the left hand is lowered—for whatever reason—is the fighter then to raise the fist to shoulder height before firing? Surely not.

Likewise, in a hooking or uppercutting motion, it would seem impossible for the fist to truly follow the power line, as, in both cases, the line itself would be at an acute angle, following the bend of the arm.

4. If one lands with the lower three knuckles, as Dempsey directs, with the body-weight moving in the same direction, will the power line always take care of itself?

3 and 4 together
As long as you are punching straight using his advice with the drop
step or following his advice about the shoulder whirl then the
powerline takes care of itself. Doing it right forces you to adopt the
powerline theory....this is why it works.

5. In the rear shuffle—and concerning footwork, in general—Dempsey directs that weight should remain well forward, throughout.

But, it would seem to me that the very act of shuffling backwards would require some kind of weight shift to the rear foot. Otherwise, I find myself, essentially, hopping in reverse. Am I wrong?

(I am now thinking perhaps, that the author did not intend for the reader to be preoccupied with the distribution of weight on the feet, but rather simply to make certain the weight is well forward by way of the slight bend at the waist. If this be the case, then, in theory, the weight will automatically shift back to the front foot after each step, no matter what kind).

I think you have it here....don't preoccupied witht he small things,
they tend to work themselves out rather well if you are doing
everything else right.

6. The instruction on stance, if followed precisely, would seem to produce one of a square variety—that is, with the torso facing forward and with no bladed positioning of the body at a 45 degree angle.

However, Dempsey does say to lift the shoulder and push it forward, slightly, to guard the chin. But, in doing this, is the shoulder to move independently of the rest of the body, or is the position to be achieved by rotating the entire torso to the right--from the waist? If it be the latter, then the stance would, indeed, become a bladed one.

Personally I just move my lead shoulder on it's own without rotating
the entire torso.

7. I find there is variance in the point of contact between my front foot and the floor, when poised for the falling step (and therefore, when in normal punching position), from one occasion to the next, depending upon the degree of bend in my knees. At times, the left foot is entirely on the ball; at others, with less bend, the left sits flat on the floor. Which should it be?

Personally I like to keep moving but I think either could be
considered correct as long as you are not either cemented to the
ground or too wobbly. When I stay still my lead foot tends to rest
flat or near flat.

8. Dempsey, in the footage, holds his hand quite low, more along the lines of the late bare-knucklers. Yet, he advocates a position with the hands held in advance of the lips, in the book. Again, I don't get it. (I suspect, here, that the author simply wants the novice to keep his hands up for protection, until he has developed adequate evasive and defensive abilities, at which point, he can more safely lower his hands, as Dempsey did. I'm giving the benefit of the doubt, in this case).

I assume that "in advance of the lips" is not to mean that both half-opened fists are in direct line with each other, but rather one just offline of the other--the right four inches in advance of the lips on the right side of the mouth, and the left 10 inches in advance of the lips on the left side of the mouth?

(I now suspect that, indeed, the author does intend for both hands to be in line, as this would be in keeping with "centerline" punching, which so many Wing Chun exponents refer to when talking about this book).

Hands are not inline....centerline has no place in Dempsey. In earlier
boxing yes but not in the later era such as Dempseys time and after.
In centerline boxing parries tend to be to the outside, in Dempsey we
want to leave a little bit of target exposed right doen the center. It
makes parrying much easier if we know where they will be aiming for
and the inside or downward parry is much easier to do than the parry
to the outside.

9. Lastly, it seems Dempsey is claiming many of the methods outlined in his volume are those used by the old-timers (i.e., Sullivan, Corbett, Jeffries, etc.)--especially the bit on the power line and three knuckle landing.

Yet, I find in Fitzsimmons' Physical Culture and Self-Defense that he advocates a two-knuckle landing, with the index and middle knuckles. What!? I don't get it.

Lot's of boxers and just about as many methods as there were boxers.
Dempsey had a great method but it was not the only one out there. As
far as I know Fitzsimmons is the only manual that advocates that
particular method...perhaps there were others and even other methods
but they have not survived.

ken