A third nodule that is associated with the pointing finger just appeared on my palm. I do not have a nodule associated with my little finger. This seems odd to me from what I have read. I understand the usual progression is from the ring finger to the little finger. How rare is this, or is there another diagnosis than DD to consider?

The three nodules are causing some contraction but not enough to cause any significant lack of dexterity. I initially noticed a nodule associated with my ring finger on my dominant hand, now I have three nodules.

"It sounds like you have (slow) ongoing progression, have you made plans for treatment of you should need it?"

Yes, apparently, it is slow. My fingers have been very flexible so that I could bend them backward quite a bit before this. They will still bend backward some, but it is reduced now. I finally looked up some references and confirmed what you reported about multiple fingers.
I have seen an orthopedic hand surgeon for the first two nodules and will see him again for the third one. The first appointment concluded with, "When it gets to 30 degrees, I will do an outpatient needle fasciotomy".
Changing the subject a bit, I asked him about anti_TNF injections, and he said the study had too many adverse reactions. I had read the paper but did not recall it, so I did not challenge him. I later looked it up, and the author explicitly says there were NO adverse reactions. I plan on bringing up the subject again at my next appointment. That will probably be an uncomfortable subject.

I live in the USA. Yes, I saw that YouTube. He did not mention any other treatment and when asked about what to avoid said that there was nothing.