Reading your question I feel like you are little misled about what Buddhism is (or maybe I don't understand your question at all). So however, I will give you an answer as I understand your question.
First of all, as I know the word "attachment" is wrongly translated from the "Pali" word "Ragha".
The meaning of "ragha" can philosophically explained by using the words like greed, sensuality, desire, attachment or excitement for sensory objects, lust, sexual desire and passion. Now, because of the "ragha" when you lost something or someone you love or even when you can't have something or someone you love, you face an unbearable pain. This unbearable (or bearable) pain called in 'pali' as "dukkha".
Now, you cannot control losing things or people and not being able to having things or people you love. Nothing and no one last forever. Things decay they brake, people age they die. Even we didn't lose them when we alive, we die eventually then we lose them in the moment of our death.
In Buddhism it teaches about reincarnation, a cycle of birth, living and death (Sansara). After someone died they reborn again based on what they did in their past lives(Karma). Every living being suffer in various ways sicknesses, injuries, pain of losing loved things, does't matter rich or poor, powerful or not, every one suffer as life goes on. So, as the cycle of livese goes on the pain (dukkha) continues. So the Buddhism is all about braking this cycle of lives and ending the continuous pain (attaining nibbana). Buddhism teaches us that holding onto things/attachments (Ragha) is one of the reason this cycle goes on. To break the cycle you have to lose the 'Ragha'. The way to lose ragha is being well aware of that everything is not lasting forever and accepting the reality of world (practicing Upekha). If you truly master this 'Upekha' you wouldn't be in pain of loses. This doesn't mean that Buddhists have to leave or stop protecting their loved ones, loved things or Stop trying to achieve things, earn money and doing jobs. People need those things to be alive, to survive. Buddhism teaches to be aware of the fact that things don't last. Love people knowing that someday we lose them, use things knowing they break, they don't last, Earn money to survive not out of greed, Eat food only to be healthy not because taste good.
Now about your question, If you understand what I explained above you will realize that helping a child to find her mother is not helping her to stay in attachment. Doesn't matter you help her to find her mother or not she always will be attached to her mother, even the mother is dead. As long as the girl don't understand and not accept the concept of 'dukkha' she will always feel the pain of losing her mother, doesn't matter you didn't help the girl or not. One cannot be removed from attachment(ragha) by just being away from others. That attachment(ragha) is a state of mind, a way of seeing the world. Helping the girl doesn't make her or you any more or less 'ragha' person. It's not ultimately helping her to be in attachment it will only be helping her to survive and allow her to be with the people she loves.
Same like that helping Bob and Alice will only be helping them to communicate and understand the situation and helping them to continue with their lives.
Helping others to live or helping them to continue their lives with ease doesn't make any bad effects on your ultimate freedom (Nibbhana). However, if someone did those things with 'ragha' mind that will affect his 'nibbana'.
My vocabulary is not that good to explain things in the Buddhism. I don't know the most suitable english words and phrases to explain these things. I hope you understood and got the answer you needed.