[Black Sheep]

I can see what you mean but when people look down on their body or see their bedroom from above, don't they actually 'see' the body or the room as it is??

Sometimes they do, sometimes they don't. It might help to read some NDE books, or better yet, experiment yourself. It can be learned, there are very concrete and time-tested practices the globe over that teach these things.

Or in the NDEs, when they see & hear doctors/relatives from above or in adjacent rooms, how does that work?

Have you ever experienced something similar? Either when meditating, in a contemplative practice, or mentally focused? One doesn't even need to OBE/AP to experience these dormant senses, it's more of a matter of awaking to them, and exercising that muscle.

What are they actually seeing/hearing with??

Would it be a hard stretch to say that science has yet to discover certain senses that is accessible but dormant? Perhaps, that western science is close, but still has much to discover?

The same with remote viewing??

I recommend reading the book "flatland" it really helps bring OBEs to a down to earth level, how certain things work, though mathematically. Remote viewing is akin to and in-body OBE :P if you don't mind me putting it so crudely.