Its blocked cause your still in the first generation. To unblock them you need to move into the second generation. To move into the 2nd generation, you need to get married and build a school for your child.
To get love points (LP) or Friend points (FP) you need to do requests, or bring them an item that they life.. For instance, for mana, she likes pink turnips, so plant pink turnips and give one to her each day. Also, Festivals raise HP/FP, so try to talk to every1, and win. To get married you need to bring some1's LP to 10, do their 10th request then get the item that allows to to marry her. For example, i married Mana, and in order to get the engagement ring, you need to do Douglas's quest, which you need to defeat a giant orc.