This is not an expert opinion, but I think that these could be street art from Venice. My best guess would be that the artist is/was local (or studying in Italy) and a tourist from your area visited and bought a few pieces and had them framed. My basis for this guess is that I've done the same in a number of places, the work seems modern (not a print and signed twice, both on the picture and the matting, which sometimes comes with the piece), and watercolor is a popular medium for this type of art.
Could you provide a picture of the numbering and label/title on the back? It may be a tag that came with the paintings or, if you remove them from the frames, the numbers and title might be written on the back. If so, I think it strengthens the case above.
Happy to be proven wrong, though.
