In regards to a cadet moving from "Junior" F/O Status to a level 1/2 or 3 F/O the following needs to be understood.
CAR (Civil Aviation Regulation) 5.172 stipulates the aeronautical experience required to hold a (full, rather than frozen) ATPL. An ATPL needs to be issued before a cadet moves from a Junior F/O to a standard F/O, and an ATPL also has to be held to become a Captain. As it stands be today a junior cadet would earn around 55k per annum and a level 2 would earn just over 92k per annum.
Although you will receive most of your non ICUS component from you CPL training there will be elements of the ICUS component that the company will need to facilitate to allow you to upgrade from your junior status. And given the pay disparity between junior F/O's and a standard F/O there is little justification for them to do so. (This had never been the case at Qantas) because there was no such thing as a Junior cadet. Therefore Qantas saw it in their interests to assist all new entrants to gain the relevant experience to achieve an ATPL (assuming the did not have one upon entry) as they would all be eligible for a command upgrade and it did not cost them any extra money.
Although Qantas has a long tradition of allowing cadets (within Qantas mainline) to gain ICUS time, this has yet to be established at Jetstar and given that all ICUS time is predicated on flying with an approved training captain at the request of the company applicants to the cadet program need to clearly understand that they may well find themselves fixed at a "junior" status for longer than anticipated. If money gets tight (as it usually does at Jetstar) and the company sees a greater pool of experience within the Direct entry candidates they are under no obligation to upgrade any junior F/O. This is because, in relation to the EBA seniority is "A major consideration" in relation to promotion rather than "The only consideration"
Good luck