Some comments:
--Like the Ottawa, Gatineau level is controlled by dams, depends on levels of reservoirs up north and is independent of local rain. Its level does not change very fast.
--At high level, all regular lines are the same. Lucifer gets gigantic, High Tension flattens out, Seuil Des Cèdres and Bonnet Rouge pretty much disappear etc.
--i might be wrong here, others might pitch in, but I don't think there would be a problem rafting when the rafters have no experience--provided the guide knows what he/she is doing. It's a deep river and swims are not too scary.
As I wrote, others may have more/different information.
By the way, July 26 is a Wednesday. I am coming back to town that day, so I might be able to go with you later that week.
--C.