Can auditing students attend consultation hours?
The easiest answer to this would be to simply ask the lecturer. A simple "Hi, I'm auditing this class, is it ok if I drop by your office to ask a few questions during office hours, if you have time?" would probably suffice. If the lecturer doesn't mind, then you're good to go. 

I would probably not agree to auditing students attending office hours/tutorials, especially in large classes. Generally speaking, auditing classes is fine, as long as you do not put additional strain on the lecturer/course apparatus. If I start accepting office hours from one auditing student, I'll have to do so from all of them. If my guest students start attending tutorials and take up other students' time from actual registered students, I would probably intervene. 

This is me, and other lecturers can have different attitudes towards their auditing students. The best thing to do is to ask.