No. Even if you are confident that you know nothing of value, regarding the immediate investigation or generally, you cannot trust that the police are evaluating you from a position of neutrality. There are endless anecdotes about police deciding in advance where their primary suspicions lay, and then manipulating circumstances to ensure the outcome matched their hunch, evidence be damned. This much is objectively true; discussion of why this happens, and to what frequency, takes us out of GQ and into debate territory. But the simple truth is, one’s innocence is largely or entirely irrelevant when dealing with law enforcement.
Incorrect and unhelpful. The police form their suspicions for their own reasons. Your attempts to portray yourself as above suspicion may actually backfire.
The most objectively true answer is, you should always have an attorney present in anything but the most transitory and casual interactions with the police. The attorney may not do anything but observe to ensure the police are properly following procedure and respecting your rights. And you can even say that directly: “I haven’t done anything wrong, and I will be happy to cooperate and speak freely about this incident/case/whatever. But in my own interest, and in the interests of your case being conducted properly so its findings can’t be challenged on procedural grounds, I require an attorney to be present.”