1) no, discipline is a land army stat
2) blockade efficiency determines how many ships you require to blockade a port and also how well you do on snagging the blockade runners for ducats
3) I never take them so I have no idea
4) maneuver rating of armies affects their supply size and help determine the terrain a battle is fought on (and who defends if 2 armies arrive in a province the same day), and yes: it also decreases the time it takes to travel from province to province
Now my question: Is it intended that a non-HRE member immediately loses their cores on different culture group HRE provinces upon losing the province?
Situation: I diplo-annex TO intending to release them after removing a couple province cores as I only wanted a couple provinces (previously vassalized due to mission). They immediately lost their cores on Osel and Kurland, having previously lost Estland and Livland to Denmark they also have no cores in those although I can't say for sure when they lost them.