Topic #3: In Islam can a boy talk with or befriend a girl or can a girl talk with or befriend a boy?
A boy and a girl can talk with each other if there is some work or if there is some other important thing while respecting each others value and maintaining moral standards.
As far as befriending each other is concerned, Allah has clearly stated in Qur'an 5:5 that it is not allowed as:
...And [lawful in marriage are] chaste women from among the believers and chaste women from among those who were given the Scripture before you, when you have given them their due compensation, desiring chastity, not unlawful sexual intercourse or taking [secret] lovers. And whoever denies the faith - his work has become worthless, and he, in the Hereafter, will be among the losers.
And Allah knows best!
May Allah help us follow what is right. Aameen.