Regulation 80 establishes the rules for organising design contests covered by Part 8. Contrary to other provisions which claim to lay down principles when really they impose rules (I am looking at you Regulation 76...), Regulation 80 lays down principles while claiming to establish rules.
Generally, the idea of this Regulation is that the various regular procedures are to be used with the necessary adaptations introduced by this Part, which so far have not been many. Furthermore we will not find many adaptations in this Regulation either.
Paragraph 2 forecloses the possibility of a contracting authority limiting participation on a design contest to a territory or part of a territory or the nature of the economic operator. My view is that either are not strictly needed as the general principles of equal treatment and non-discrimination would be enough.
As for paragraphs 3 and 4 they are very much in line with pre-existing principles as well: in case of numbers being limited, the selection criteria need to be clear and non-discriminatory and the total number of candidates to be selected enough to ensure competition. As I said above, principles, not rules.