1. If taking/purchasing a brick(s) do you always have to pay at least one coin? This is what basic rulebook say.
If you take only a free brick, then you have to pay nothing. Page 4, section "buying bricks", point 3, 4th sentence of my German rulebook says:
"Der Spieler muss mindestens 1 Baustein kaufen. Auch wenn er einen oder mehrere Bausteine kostenlos nimmt, ist dies ein Kauf."
"The player must purchase at least 1 brick. Even if he takes one or more bricks for free, this is a purchase."