Well,
1) She almost always showed up as a separate entity when they were talking (any time it wouldn't be too much of a distraction for him), and the flashback Uriel was showing him is certainly not likely to be precisely representative of what a person standing there at the time would have seen. She's 'perceived' as an outside force, for the sake of being perceived at all.
That's reasonable.
2) I think you missed some of the point of this bit of my comment:
I think (based more on cryptic comments from Jim than anything in the books to date) that Lash did survive in some form, but she may very well not be present in the same manner, or her voice (if she even has one at this point) might not have the power to properly balance the dark-Lash's comments.
I got your point, my response just wasn't clear. I was pushing against the Lies whisper being Uriel. If Lash is still a bit around and on Uriel's side, why couldn't she be the whisperer? Power-schmower, I'm not sure that's necessary for an explicit whisper whose sole purpose isn't to influence, but to remind.
But, if you do want power, I'd remind you what Uriel said to Stu in his job offer. Uriel can take the ruins of a spirit and build on it. I'd need to go back to what Uriel said about Lash's biting-of-the-bullet, but what if enough of that survived for Uriel to build on? [Partial </crazytalk> tag here.]
Or maybe Uriel just wanted to do it hands on, because he sort of promised Harry that he would.
That's a big maybe. <broken record>And given everything else in this series, it seems too easy.</broken record>
Oooh, thought just occurred to me. If Uriel had Lash do it, then Lucifer has to do one of two things: 1) acknowledge the possibility of redemption and that Lash is back in God's fold, or 2) assert that Lash is not working with Uriel, which would still leave Uriel with a seven-word whisper. Uriel wins either way.
Hmm. So the mystery remains.
Can we get this to be the motto of the DF Spoilers board?