After now achieving the Masters Rank D, I just wanted to add a few of my thoughts here for others thinking about this in the future.
I went for the DK KS first, and I'm not sure how getting that might have affected my ability to achieve the others. But DK certainly seemed the hardest by far, and took me 8+ months of grinding that game on a near daily basis. In contrast, each of the other requirements took only a matter of weeks.
After DK, Crazy Kong felt pretty easy. Would it have felt easy had I tried that first? I'm not sure, because many skills/techniques of regular DK carried over the CK. Anyway, I'm pretty sure regardless that CK is the easiest of the 4 to achieve.
I found the DK3 and JR requirements to be roughly equivalent, but with the JR KS being perhaps slightly more difficult to achieve. I think that's because the KS with limited lives requires so much precision, and the game length to get there is a bit longer too.
The DK3 requirement is close behind JR imo, even using the sacrifice strategy. But unlike JR, you have quite a bit more leeway in terms of your precision of play. On the flipside though, there's tons more going on you have to be paying attention to in the game. I thought the JR chains level was crazy tough with everything happening there, but the DK3 boards (especially the grey board) took that to a whole new level. Your skill at DK3 also may depend on if you've previously gotten good at shooter games like this too. I've played a lot of classic arcade games casually, but had never really tried to master any until DK. Anyway, I'm glad DK3 is included in the requirements. It's a fun and much different game compared to the others that I otherwise wouldn't have stuck with and come to enjoy.
If who has already achieved a DK KS is thinking of doing the rest of the requirements, there's no reason not to go for it! If you want to start with the easier requirements first and see how it goes, give Crazy Kong and DK3 a try!