Finally, if the first change is adopted, I don't see the need to ask for a date of birth. Of course this is needed for directors but otherwise I think it is unnecessary. It would also be better from a child protection point of view meaning that someone who gained access to the membership lists wouldn't be able to immediately identify minors. It would also help guard against ID fraud given that they often need dates of birth.
If there is a requirement for a signature of someone over 18 then you at least need them to check a box saying "I am over 18" even if they don't give an actual date of birth.