A question about Imaginary Friends

[MaxJ1800]

I'm considering a story idea, but there's something I need to consider. How much can an Imaginary Friend look like a human? I know there have been Imaginary Friends who looked reasonably like humans, for instance, the Imaginary Mac and Goofball McGee.

But they each had some feature that gave them away as imaginary, Mac's tongue, Goofball's trunk. And no one really mistook them for real humans, except Frankie, in Goofball's case.

What I'm wondering is, can an imaginary friend look enough like a human, to actually pass as a human. For instace, could an Imaginary Friend look enough like a human child, to attend school with kids and not have anyone notice? Or would a human-looking Imaginary Friend have at least one feature that would give them away as imaginary, if anyone saw it?