1. Registered, by "effective strength", meant my proposal for handling fleets on blockade, that is, reducing number of ships counting as on station. In that sense, it is separate from the other 3. Other than that, I think we're on the same page here.
2. As to the number of missions, who knows? That's a matter for some thought. I, too, would prefer to keep the number fairly low, which means telescoping some into others, where possible.
3. There are 2 senses of pursuit possible: (a) trying to catch a fleet at sea, & (b) pursuing a beaten enemy. IMO, only the 1st might be a mission, & could as easily be called "interception", or something else. Your phrase, "actively searching and destroying enemy fleets" is just what I meant, & works just fine, except it involves more typing. It would differ from general patrol, though, where, like blockade, a station is involved. But I don't want to insist on it, or on any of the list I gave. Except blockade, I just meant it as a starting point. What can be cut, should be.
4. Gwalcmai, I agree, but your post made me think of one possible problem. Currently, armies don't load in port, but from port to ships at sea. But they do unload automatically. If this is still the case in EUIII, it could complicate things. I'd like to see troops load, & stay loaded, in port. This means the only way to beat a blockade is to fight your way through; I don't see evasion, unless it's possible to start the fight & retreat to an adjacent sea zone. (& would the AI ever do this, as things stand.)