Add Facets to Triangulated Surface

I have a surface created from triangulations... I need to join six triangles to create a polygon... 

Another choice would be to move the vertices of the centre of the resultant polygons to get a faceted surface... Any idea on how to do that? 

Then I would like to create perforations in the surface based on a sunlight parameter... 

The GH file is attached below. The first patch is where I've reached right now... 

Thanks in advance...