Regardless of the Resource used to colonize, both prices will scale accordingly, e.g. colonizing your first Area with Kröwns and second with Food will cost the same Food as if you had colonized the first Area with Food.
If an Area has already been colonized by another player, it must first be decolonized with Military Units. This cannot occur while the Area owner has active Clan member inside the Area. Decolonization of an Area will cause any buildings to burn and take damage over time, this damage is significantly less than the damage buildings take from sources such as an Earthquake. These buildings can be repaired and claimed by any player that then colonizes the Area. This can allow Clans to access other Clans unique buildings e.g. The Hall of Skalds.