Are there official VIZ translated scans for the raws we provided?
Mifune's statement says the speed at which he swings his sword to create the air-chakra slashes is LS, which would only imply the blade swing is LS and not inherently the air-chakra slashes.
Additionally, it shows his Kyuubi-amped self doing the feat; however, I've been told that it's the only time he performs the feat which could explain why they use the Kyuubi-cloaked Mifune, either way it's something to consider. I've always seen it that the databook quote is always in reference to the scene in context if a panel is accompanying a statement, but some disagree. If we argue that only Mifune's sword swings that produce the air-chakra slashes are only lightspeed with the Kyuubi amp I don't think there's anyone who directly scale to it, if we argue that only Mifune's sword swings that produce the air-chakra are lightspeed in general then still I don't think anyone intercepted a blade of his mid-fire of his air-chakra slash (I could be very wrong), and if we argue Mifune has lightspeed strikes in general then I'm sure a slew of people scale.
Raikage Ay's statement uses "gotoki", which if you look through the pdf Cyber sent has examples for "gotoki" as follows: "dream-like" and "as if he were the president", both of which are clearly similes. Cyber brought up a valid interpretation that maybe the simile is that Raikage isn't literal light but is only lightspeed. As I see it, that interpretation is just as valid as saying that the simile is comparing Raikage's speed to lightspeed. I'd currently argue that Raikage's speed being lightspeed is the simile though as it's implied he needed the lightspeed teleportation to reach the battlefield, which why would he if he could move at the speed of light.
To provide a counter to my own argument, I remember someone mentioning that it could have something to do with the unique description of the lightspeed teleportation, but I don't know enough about the technique to comment. If you're going to argue that this scales Raikage to lightspeed, keep in mind that the
Anbu have the literal same statement with the same use of "gotoki" (top kanji section pointing to the top picture, middle line), which may call into question the validity of applying a rating using Japanese grammar for similes. I feel like "possibly SoL" for Ay would be the most generous rating.
The only arguments against Itachi's lightspeed water bullet is hype-text-hyperbole or outlier or inconsistent. The statement exists so it's worth mentioning at least. As for arguments for it, kid Kakashi being toted as a lightning-timer is a pretty good one. Looking at their profiles though it seems that may be inconsistent.
I feel like if we had some official databook scans to support one interpretation over the other that'd be nice, but I know later end Naruto and Bleach databooks are notorious for no official translations.