As a Photographer one year I quit taking the family pics with the failures caused by bunny ear fingers etc. Also I used to picture around 400 students where I had most success then the honesty system completely broke my faith in parents and childrens honesty.
What you are doing taking individual pics is sound and possible if they live near you if not you have to be flexible and dare I say devious.Also real facts such as how many in your family eg these days with 78 of Wilma,Me and children G Children,GGGrands married ins married outs.
Like your pens made this way.
Enjoy the chase Peter.
Peter.