Q3.0.6: Can I force the output of (face-list) to a buffer?

It would be good having it in a buffer, as the output of (face-list) is too wide to fit to a minibuffer.

Evaluate the expression in the ‘*scratch*’ buffer with point after the rightmost paren and typing C-j.

If the minibuffer smallness is the only problem you encounter, you can simply press C-h l to get the former minibuffer contents in a buffer.