Players may rearrange their hand cards and change their orientation to help themselves remember the information they received. Players may not ever look at the front of their own cards until the play them.
The discard pile may always be searched for information.
Hanabi based on communication and non-communication between the Players. If one interprets the rules strictly then players may not, except for the announcements of the current player, talk to each other.
Ultimately, each group should decide by its own measure what communication is permitted communication. Play so that you have fun! …