So, if I understand the answers correctly:
1) A blockaded planet is prevented from contributing to the empires global pool of minerals, organics, radioactives, research points and intel points.
2) Except for
a) its inability to contribute to the empires global pool and
b) the effect of enemy ships has on its happiness,
a blockaded planet can still function normally. In other word, it can still draw on the empire's global pool to construct anything.
3) If the blockaded planet has the only space port in the planetary system and the Empire does not have Natural Merchant, then all the other planets in that system are prevented from contributing to the empires global pool.
Would this be an accurate assessment?