Hi to everyone!
I also think that all questions should be closed. We can include at the end an open question: Describe Europe in three words and why? But this last question is for a qualitative analysis, not quantitative.
I propose 15 questions maximum. Of course, include age, sex and city.
It is a great idea to work on a Word document with comments in different colors. If you can not through the web … Google Drive gives the option sharing with all partners a document on the Web, and we can write at the same time.
Greetings from Talavera
Idoya