If the phone has been lawfully seized during the execution of the search warrant, then the police can hold it for analysis to see if it contains any evidence and if there is anything that the police deem to be evidence on the phone, then the phone can continue to be held as evidence for trial.
As for the information on the phone, it falls under the same rules as the physical phone itself. If there is evidence, it will be held.
If, after analysis of the phone, it is determined that there is no evidence on the phone, the Federal Crown can authorize the police to return the phone, which would include the content on it. If they refuse to return it, but acknowledge that there is no evidence on it, then a Application can be made to the court for an Order that the phone be returned.
This is the normal process involving seized cell phones.
However you are clearly looking to get access to the data on the phone immediately. I know much more about the law than I do about different types of technology, but with certain phones, I believe that the data is backed up on the cloud, outside of the phone, so you may be able to access it without the phone.
If you have no other means to access the phone you can make a request, in writing, through the Federal Crown for the police to provide this number to you. If the police have begun or completed their analysis of the phone, then they could provide this to you. If they have not begun this yet, then they will not be able to get you the data as they can only access it using their specialized tools, as it maintains the integrity and continuity of the phone when seized. This is required in order to satisfy the court that the data on the phone is as it was at the time it was seized.
If they have completed the analysis and refuse to provide the information, then you can make an application to the court to have this information from the phone provided to you, however you would have to satisfy the court that there are sufficient grounds to satisfy the court that they should order the police to turn this information over. If this is a matter of life and death or if the data on the phone is essential to the defence, then this could provide sufficient grounds.
However the best place to start is with a written request to the Crown for the information in the phone .
Bear in mind however, would result in acknowledging ownership or an interest in the phone and the data on it, which, if there is evidence found on it, could be hurtful to the defence. Such a request should be made through a lawyer.
Please let me know if you require any further information on this.