CTC Wings requires the partnering airlines to be fairly accurate in predicting how many FOs they will need about two years in advance. If they over estimate, the excess graduates can go into the hold pool. If they underestimate and CTC does not have enough graduates, the partner airline has to go elsewhere and hire self sponsored students to fill the shortfall. If you look at OAA's employment report, you'll see that EasyJet hired about 17 from OAA in 2006, which was most likely done because they underestimated their requirement in 2004.
CTC recently expanded their capacity. I suspect the main reason they started iCP is to sell excess capacity because they may have over expanded beyond what the airlines think they will need. Indeed, iCP may have been the first sign that airlines were projecting a slowdown, though it could just be a sign CTC's expansion was over-zealous.
The iCP graduates who do well enough will have priority for the Wings ACP SSTR and if there is another shortfall like EasyJet had in 2006, they will probably pull iCP graduates from the hold pool before they venture further north and hire OAA graduates.