It's for trans men, not trans women. It's not replacing any language, it's in addition to, all you would have to say is 'i am a woman and please say breastfeeding' and they'll do it. It's breast/chest feeding
No! If anything it should be the other way around. mother and breastfeeding is the automatic and natural assumption. If anyone has a genuine problem with that then they can request the words be changed.
However, you do realise the sort of psychological fragility this points to is not best suggestive of becoming a parent. The very first sound a baby makes, in all languages, is Mama, Ma, or similar ( apart from gurgling)