Neil
"In this author's view, being unable in principle to find out everything about the world's contents implies that "bit" (information) is derivative and subsidiary to "it" (real objects.)".
Logically (ie in principle) we could find out everything, because what we can know (which is the equivalent of physical existence) is limited by the physical process which enables knowing. Though in practice I doubt we will ever achieve it, but that is a different point. I presume your statement is not an allusion to all the possible alternatives that might exist, but we can never know, as that involves belief, not science. However, that is not what causes 'bit' to be derivative. Information is information because it is representational of something else. It can be an it (ie real object), of itself. For example, light, vibration, noise, etc. And then one has to establish the extent to which it is valid information (more commonly known as knowledge), ie corresponds with physical existence, as invalid information is useless.
In respect of observation, the more pertinent question is what has observation (informed or otherwise) got to do with it. Observation (measurement) is a process which involves the receipt of physical input (eg a photon based representation of what occurred) which is converted into a perception of that input. So observation, or indeed any form of sensing, has no effect whatsoever on the physical circumstance. Other than, somewhat obviously, the input ceases to exist in that physical form as a result of that interaction. But then that occurs if the light had interacted with a brick instead. The only difference being a brick does not have the capability to process the input receivable. Observation cannot affect physical circumstance because the sequence order precludes it (ie the input is received, it already existed before the subsequent processing), and that processing is not a physical process, it does not involve an alteration in physical form. Apart from the simple fact that what is received is not the existential sequence (commonly known as reality) anyway, but a physically existent representation of it. So there is no interaction in observation between the observer and reality.
Put simply(!), whatever reality constitutes, it is physically independent of the mechanisms whereby it is detected. So why do we have a physical theory purporting to explain physical circumstance, where observation seems to be integral to existence, as opposed to just being the mechanism whereby we find out what happened?
Paul