Re: Hurtful comments about family size...
Just keep letting it roll off the back! Say "we are blessed" and the like. People are going to think what they think and just let time change their minds (as they see you joyfully raise your children). I have a few aunts and uncles talk negatively about our family size and we only have 4! Some of my family is concerned about my health due to pregnancies/c-sections and get worried when we have babies and will voice their concern (I think that feels worse than negative comments... maybe because it's more made out of love and worry).
I talk with certain family members about ouir plans about children because I value their input. I wouldn't "warn" anyone.