Sakuya is daughter of restaurant owner, name of main character mom is Yasuka,
As story progresses the money you collected will be given automatically, Anyway there is no other way of making money other than collecting the hidden money in each place.
When you say, you have collected all money, then it means you should have unlocked cheat menu. (ie you got money from Minato's and ice cream parlour as well, which is available only after completing all the quest for Sakuya)
But if you havent completed the cheat menu and havent seen the minatos house, then you need to go check outside your home at night