I keep Reidi, and I really don't think that that is what she is... but she could be a Kuda/Reidi hybrid, or a something else Reidi hybrid. As for what you should keep with her, I'd stick with the larger, more hardy tropical species, like Reidi.
I love Reidi, they have the potential to be really colorful, and I like their more sleek look. All seahorses have different personalities, but I can tell you about my girls. My girls are really active all day long (they don't just pick a hitch and sit all day), and they have come to recognize me and will dance for me at the glass (begging for food) whenever I'm near the tank and they come to the top hoping I'll stick my hand in so they can hitch to it... seahorses do have extremely good eyesight (possibly similar to eagle eyesight).
Erectus are very popular. They have a broader body and are far more likely to have cirri than Reidi and Kuda. They have the potential for beautiful patterns, but their colors are more muted compared to the bright colors possible with Reidi (not that color or pattern are ever guaranteed with any species). I haven't kept them, so I don't know much about their personality. They have a reputation for being one of the most hardy species, but that could be a problem in your case, because they also have a reputation for being the worst species to mix with, because they are so tough that they can carry around a lot more things that will get the other species sick (like your girl).
Kuda are slim like Reidi but slightly smaller in length and not as brightly colored. I know next to nothing about their personalities, but I would personally avoid them at the moment. There isn't anyone in the U.S. breeding them on a large scale, so unless you get some raised by a hobbyist (which isn't likely) you aren't likely to get healthy seahorses. The ones in the U.S. right now seem to be pen-raised in the ocean & imported, and there have been a lot of disease problems with them.
I would also personally stear clear of more sensitive species like Ingens (which would be difficult to get anyway), Barbouri, and Comes (which aren't available CB anyway), and that pretty much covers the tropical species available in the U.S. (except dwarves, which are an obvious no-go). So, it looks like I'm pretty much recommending Reidi at this point

Basically, I would recommend Erectus, except that by the time you get your new SH, you are going to be so attached to cocopuff that it would probably be preferable emotionally to risk getting your new SH sick than to risk getting your cocopuff sick. Of Reidi and Erectus, I think Reidi would be less likely to get cocopuff sick, especially since I could easily see her being a hybrid of Reidi, but I don't see any Erectus in her. Of course, if you get a different I.D. on her species, my recommendations could change...
My last bit of advice is to use
www.seahorsesource.com to get your SH. Dan is super available to the hobbyist whenever you have any questions or problems, and he is very knowledgeable, which I think has extra importance since you are going into this knowing you might have problems. He also sells many of the medications you'll want to stock up on off his web site, and he knows their proper usage and dosage to walk you through it if you need them (and he will work to get you more in a pinch if you need it). He also has really healthy SH. His erectus typically have a waiting list all the time, but I think his Reidi are usually readily available. I would caution you against getting Reidi from your LFS, even if your LFS orders from ORA. One, the extra shipping, acclimation, etc. from wholesaler to LFS to you puts them through extra stress that you really want to try to avoid with this plan, and also b/c I have been told that ORA has been mixing a few of their species (which adds extra disease risk for your girl that you really don't want to mess with in this case), and that some of the Reidi being shipped to LFS by ORA are being imported from other unidentified captive sources (read: could be ocean pen-raised in Asia, or from seawater flow-through systems) and LFS owners have told me that some batches aren't coming in very healthy.