Actually the question is in the title. Anyway I would like to repeat it:
Question: How I could apply two different CCActions to two different CCSprites and run them in the same time on one CCLayer?
Thanks in advance!
The CCLayer has nothing to do with that. You just send the runAction message with the action one after another to have the actions start running at the same time:
id action1 = [CCFadeOut actionWithDuration:1];
[sprite1 runAction:action1];
id action2 = [CCFadeIn actionWithDuration:1];
[sprite2 runAction:action2];