Although I have created my own prints for a long time, until recently I hadn't put in the think time and money to really dig into why sometimes mysteriously, to me at least, my prints came out too dark or with bizarre colors (just like your scenario). Long ago I read multiple books about color for photography, but without having a tool to explore my specific scenarios, it all remained a bit abstract and useless to helping me achieve my goals. Things were basically hit or miss. Thankfully I got more hits than misses, but I feel your pain. I recently acquired Chromix ColorThink Pro and it has opened my eyes up to what the heck was going on with my prints in a way that soft proofing didn't even remotely convey to me. I am not necessarily suggesting you buy the tool, as it is rather expensive, especially in relation to an R2400, but being able to explore with it really enlightened me. Most of the time I have seen articles and posts discussing paper, printers, color spaces, or similar topics I can now tell that the graphics were generated by ColorThink Pro.
There are many potential things that may be causing you headaches like this. Rendering intent, the paper's capabilities, monitor calibration, double profiling, no profile, wrong profile, bad profile, bad printer, bad ink, wrong color space.
I would recommend checking out
Camera to Print and Screen (CPS). It will help get you on the right track.
My previous printer was an R2400. It was a good little printer and can produce quality output. If you send me the photo (even a small 512 pixel version, just attach it in a reply) and tell me the profile you are using with your paper and the rendering intent you are outputting with, I can tell you in a jiffy if just based on these variables if the print will come out dark. I actually intentionally went through this exercise recently so I could demonstrate to a group of students the very phenomenon you are describing happening.
Are you printing from the JPEGs you posted? If you are, I will just use one of those. Just tell me the other variables. I am going to guess you aren't as the JPEGs have no profile attached to them.
Lastly, changing the rendering intent is probably the easiest way to get things more sane looking. Perceptual is likely your best bet when things are too dark. I would guess you are printing with absolute colorimetric as the rendering intent. Often times it can be quite dark.