1. Criteria for setting priority. How is priority established? Is priority guaranteed by the fact of presenting firstly a document against other document that is potentially incompatible?

The time at which deed is submitted will be decisive element for establishing preference between two or more registrations.

In case of reservation of priority,  it causes legal effect of preventing registering or recording any other document related to that property. Priority is officially assigned by an entry.

2. Are there any possibilities of that a document presented later may go ahead or prevail in priority rather than other documents or deeds presented earlier?

Only if there are some legal problems.

3. Let’s suppose a document presented firstly that consequently holds priority but is affected by defects or lack of legal requirements. How long would it keep priority against other document presented later?

15 working days.