I can't find where this info is coming from.
I don't think you can change the text on the OAuth screen without some major overrides from your .js file (not even sure this is possible)
However, the logo comes from the developer key configuration which is a URL to the LTI server pointing to the icon image. It's the #6 field from the image on the admin guide page:
You wouldn't be able to override the image from someone else's LTI app very easily, but if you were developing your own LTI this is how it gets there in the first place.
Ref: How do I add a developer key for an account?
It shouldn't be any problem doing it for any application that isn't using an Inherited key. An admin can easily change these for Account keys.
This isn't really an LTI question as any application could be using a developer key for authorization. That is, it is API calls that are being authorized, not LTI.
Retrieving data ...