Yes, can choose revaluation model for land and cost model for rest of the assets classified as property, plant and equipment. However, they will need to revalue each piece of land it has and not any specific piece of land that it owns.
Yes, the company can determine the useful life of asset without the assistance of qualified valuer with the assistance of technical person within company since the IAS has not provided any specific guideline with respect to personnel for revaluation.
You determine the residue value of asset by asking the supplier, assessing the market value at the time of disposal, the exchange value that can be obtained at the time of its disposal etc.
