Oh shame, I will be in Austria skiing during that time, otherwise I would show you around.
Besides the typical things like Charles Bridge or Prague Castle, I can recommend Vyšehrad. It is an old fortress which was transformed into a park, and it sort of stands above the surrounding buildings, its very beautiful and it has some nice views on the rest of Prague. Petřín is beautiful as well (and the Petřín tower is worth visiting too).
Also, we have these amazing guys that make great videos about what to see or what to avoid in Prague, maybe your kids can watch some and choose if they would like to visit some specific sights.
