I think that Kumi taking the form of Yuri was the yellow knifes way of bringing Kumi happiness. Because Yuri also came out of the yellow knife which sent Kumi insane. Kinda along the idea of giving Kasumi happiness by taking the form of her brother in her head. The yellow knife gave Kumi Yuri's appearance, but Kumi rejected it not wanting to destroy Yuri. This gives insight as to the aliens not totally being able to wipe out the person they fuse with completely. This would be why Kumi still had the urge to fuse, and if you think about it Kasumi was only trying to save a freind in the end. But she sure did recriut a lot of yellow knives in the process. My guess that was the yellow knife acting in her.
At least that is what I got from reading it. Like Mr. Tomizawa said he left it open to our interpretations. So several spins on this scene will pop up and each will most likely hold true to that interpretation. Diffrent veiws and takes on a single scene can also lead to a little more clarification of this art.

No Monami was the one that said "Kumi isn't the type to think of herself". Kasumi really cared about Kumi so that's why she wanted Kumi to fuse with Yuri (like all borgs want to do) Monami was involved with what happened with Kasumi and Kumi when Kumi was in the hospital the whole time

Hmm... an error of the translator. Well, I never thought of that, but that is a possibility too. And if it is, it is an EXTREMELY IRRITATING error!

Another thing which I found rather... amusing. Not an error or typo, but I wonder about Tomizawa's intention of drawing something in Book 1...

(I don't want to put up the picture coz it's rather obsence. Sai will murder me if i do. Need official permission first...)

In Book 1, for Operation 8: Hyper Growth, I really wonder why Tomizawa did that drawing of Yuri... erm... *hmph*. If you don't have any idea what I'm talking about, can say it's a bad thing... Perhaps Tomizawa was being naughty or just... *cough*