This comes from the Wings ATP FAQs on their website:
"The ATP hold pool serves to augment the CTC Wings Cadet numbers and we will put CTC Wings ATP pilots forward for placement when we are unable, for whatever reason, to place cadets with our partner airlines".
On the basis of this, it seems to me that if there are already Wings Cadets in the holdpool (on the basis of various PPrune posts), the chances of Wings ATP pilots being offered a position would be a very long way off.
bf