Annexing vs Colonizing vs Trading Post on Special Resources

[GreatGuardian]

Can anyone explain what the differences are between Annexing a terrain on a special resource and founding a colony?
I understand that each will start with different level buildings and population, and that one is done via Centralization researches while the other via Colonization researches but what about the following:

Is an annexed special resource automatically indestructible, since players can't destroy annexed provinces?
Does an annexed special resource province suffer from distance penalties?
Is resource transportation between the capital and an annexed special resource done using supply wagons or supply depots?
Any other significant difference that helps us to decide whether to colonize or annex a special resource?

[Madzoism]

A colony can become indestructible if its ownership is kept for 2 weeks after reaching 8th level of the fortress. When this period is over, the colony receives the same status of annexed provinces. It only doesn’t have a common border with them. If the fortress of such a colony is demolished, it does not drop a level. The defender can reconstruct it by paying the necessary resource amount.