I agree.
Joshy92 write he is sure Emma would be a great mom. but honestly we don't know.
In the other hand, we have seen that Lucy is always here for the one she loves.
Always putting their well-being before her own.
All her life, she was in the shadow of her big sister. She was the "second" Lloyd. She could had became angry, jealous, bitter, hating Charlotte and her daughter. But no, she unconditionally love them and will do anything for them.
No doubt she will do the same for her own children.
Also, unlike Charlotte who is overprotective over Emma, I think she will let her kids experiment life by themself. Always watch on them, but at some distance so the kids will gain self-confidence.
I'm sure she will be the greatest mother.