I agree with what you suggest for the first part of the form (follow the text with the underscore).
Do the form as nested list...1-5, 3-5. That allows for Disabled to be at the margin and Yes/No to begin in cell 3.
As for the squares...I suggest that you use a full cell to represent each square and put a TN before the beginning of the form to let the reader know about the change to print. The UEB square symbols WOULD follow print, but, as you said, would be very cumbersome to read.