According to the definitions given.

"Antepuestos" refers to elements that project from the facade beyond the building line but which are a functional part of the building:

"Masonry piers are often used to support internal loads on small residential buildings or to support projecting building elements such as bay windows, porches, and additions."
http://www.oldhouseweb.com/how-to-advice/masonry-foundations...

"minimal use of bays, towers or other projecting building elements"
http://webapps.cityofchicago.org/landmarksweb/web/styledetai...

"Zone of Articulation:
This is defined as the horizontal zone between the outermost plot line and the finished building line. [...]
Above ground level it should contain all projecting building elements and details including
balconies, bay windows, fins, louvres etc."
http://www.rbkc.gov.uk/idoxWAM/doc/Other-777221.pdf?extensio...

"Projecting architectural elements" would not be right here, because signage, for example, is quite often regarded as an architectural element. It is not a building element, however. Nor is "structural elements" right, because there can be functional building elements that are not strictly structural.

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For "superpuestos", a suitable term would be "fixtures", elements affixed to the facade:

"Fixture: An appliance or device attached to the facade (e.g., awning, sign, lighting fixture, conduit, or security gate)."
http://www.nyc.gov/html/lpc/html/glossary/glossary.shtml#f

"Where possible, awning fixtures and canopies originating from the building’s earlier historical periods should be retained and repaired. Whenever appropriate, new awnings should be complementary in placement, proportion and color to the building’s original fixtures and to existing awnings and canopies of adjacent buildings."
http://www.marshallilmainstreet.com/index.php?option=com_con...