Q. Is there such a thing as an "Illegal hole placement" on a green? Is there a criteria used as to where on the green a hole can be?
A. There is no illegal pin position.
It is only recommended that the pin be so many paces from the edge. Typically the pin is in reflection to where the tee placement is, so that the hole plays as close as possible
to the correct distance.
The pin can be placed any where on the putting surface, and for that matter, it does not have to be on the putting surface.
Q. What is an "x-ed out" ball?
A. An x-ed out golf ball is a ball with a blemish.
Typically it will have a flaw in the cover. Maybe a dimple isn't correct, the seam may be more visible or it just doesn't comply with the standards set by the U.S.G.A.