1. fleets question already answered in that if the turks don't have ship there and you do, you auto blockade the section and you have to sink any turkish ships there to maintain blockade.

2. assasins. if VI, syria is a must. else, try to whack emissaries, princesses, and religious agents in your provinces. Cancel the mission if you have to leave your own territories. Do this until reasonable valour.

3. Ludens is right. For all the historical heroes, look in the \campmap\names directory and browse the text files there to find their birth dates.
I would personally try to train only royal knights the year the hero appears in my best province so he gets the best armor and weapons available.
royalknights or equivalent is the best as they get updated throughout each era and hence doesn't become obsolete.