1- when i use the torian super breeder ability, does it help if my approval is only 99%?
Nope. Any planet with less than 100% morale does not benefit from the 4x population growth. See 75% morale for more details.
3- what are the level of approval should i keep it for optimizing population growth? i heard somewhere the numbers were 100, 75 and 45.
-- 100% morale = +100% population growth
-- 75% morale = +25% population growth
-- 40% morale (I think) = no population growth
-- Some where less (not sure where) = population loss
The 45% morale is probally to provide a 5% range of morale for your population to grow into until they stop growing again.
6- how much is a sector and a parsec?
Its based upon how quickly a ship with a speed of 1 can travel in one turn. Actually distances measured in terms of light years is nonsense, since nearby mass affects ship speeds. Greater nearby mass slows down ships using hyperdrive while less speeds things up. This can result in 2 ships reaching their destinations in the same time despite one heading to another planet, while one heading to another star.
Its reason why things look so close together. Actually distances really does not matter much.