For the length of injuries, I agree they should be decreased, about 5 days is reasonable, I guess.

For condition and morale, no, they should go through the usual. Especially condition, managers would be training players to 0% condition just before the season update, and managers don't kill their players in real life to let them recover over pre-season, they still go through normal training. Some players even go for international tournaments during pre-season.

Also, aren't yellow cards removed at the end of the season in real life?