Hi Quim and Pau,
TL;DR, the suggested design icons are men.
I realize that it's not the best to make a negative comment without offering a solution, but here I go. Both of these suggestions for the design icon read as men (the first even being called "man" that refers to mankind most likely but no one ever thinks of a woman, and the second being a fairly stereotypical architect bald-with-glasses look which I suppose could sort be a generic person but doesn't read as anything other than a man to me, personally).
While I know that you have no intention to imply anything in that regard, if I were approaching as a volunteer and a woman it would (maybe only subconsciously) read to me as if things are a bit man-centric.
I would prefer that not be the case.