Are elements with position: absolute; able to have a height, width, padding, etc. without changing it to display: block;
Short answer: yes.
Long answer: see http://www.w3.org/TR/CSS21/visuren.html#dis-pos-flo (or SLaks's answer).
Hovewer, this change refers only to the visual display model of the element. The CSS can't affect the content model of the HTML element since CSS is applied only after the document is parsed into DOM tree. So span element can never have p or div children, no matter which styles are applied to it.