heres the real question. since this is purely hand to hand; is rand's style of martial arts an internal form or an external form. because a master of internal form will always best one of an external form. if they are both kung fu (cant remember what exactly iron fists form is ><😉, since it is a defensive style, the one who attacks first will most likely lose
internal forms of martial arts > external forms.
in otherwords, forms of martial arts that spend a lot of time conditioning the mind as well as the body (any martial art that has chi at the end) kung fu as well, prepare the user for fighting better than a form thats is more externally focused on just the physical aspects
looked up shang-chi on wikipedia for whatever thats worth. apparently, altho his skill in kung-fu is high he is not mentioned to have knowledge in any other martial arts. so id say this fight would go to danny as knowing more than one martial art is > to knowing just one. and id venture that danny is good enough to pull off a win