Usually it's the males that give their children their first name or a variation of it. I don't know about vanity, but I think it can be confusing when two people in the same house have similar sounding names. I think Alice would be a really cute middle name for someone whose mother's name is Allison. Perhaps it would be a little strange if the daughter were "named after" the mom, but if the mom just really loves Alice, I think it works!
I plan on using a variation on my name in the middle name spot for a future daughter. My name is a variation of Mary so I want to use Malia as a middle. That name has other importance as well though. I know of a lot of mothers that use their name in the middle spot, but I've never seen it IRL as a fn.
Never. And not because I do not like my name. Because of the emotional baggage involved. I have never known a girl named after her mom who was happy with it.