All of the aircraft I know that are modified for scientific purposes are still CofA aircraft as the scientific purposes are normally tied AOC work.
That may be the case, but the question was
Does anyone know if there any types of aircraft that The owner can choose to Be annex 1 or annex2 or easa/ non easa
which is independent of the fact that obviously these chose to not go Annex II, even though they could. The reasons may be manifold, but that is another story.