My index fingers are longer than my index fingers - I often wondered if it's because I'm mtf trans but looking at the list of things that are on that list some match some don't. Fairly close to 50/50 though. FWIW my wife who is also trans has slightly longer ring fingers than index fingers
"The more this, the more likely that" is utter silliness as it is not really science, as it does not really predict anything on an individual level. Even statistically speaking the correlation is so weak it's basically meaningless. If for example a high 2D:4D person had depression 95% of the time and a low 2D:4D person only had it 2% of the time I think you could draw a relevant conclusion - but it's more like 9.1% and 7.8%. Interesting, but beyond mild interest who cares? It won't tell you by looking at someone's fingers or not whether they have depression or anything else about them with any reasonable degree of accuracy. And of course the most important thing is to treat the people with depression.... not treat the people with high 2D:4D.