[g_p]

Admittedly approaching this with a non-US perspective, but it seems strange to me that PhD students approach their advisors to see what the project/approach is.

Is it normal (in the US?) for a PhD to be as "guided" or prescribed by the advisor as you suggest above? Perhaps my experience differed, but I went for an advisor who takes an old-fashioned "independent research" focus. That's not to say they were unavailable or disinterested; rather they were there to offer input and guidance when needed, but not to steer or even direct. It was up to me to plan what I wanted to do, when to do it how to go about it, what to write up and publish, which conferences to bother with etc. Perhaps this is unusual, but I felt it was a key part of the experience to deliver your own major research programme.

I'd definitely agree that if you can't ask the questions you outlined above, or if they can't answer it, that is a big red flag. A PhD is about learning to ask questions fundamentally, and then set about answering them, so may as well get started by asking your advisor. I'd also try to get an understanding of the culture of the group and practices, since some research groups have more of a "lab" culture where everyone works as part of a bigger project, while I was involved in the opposite - everyone had their own "thing", but would work together when it was helpful.