If one of those creatures can't attack its owner that turn due to a spell or ability (such as Chronomantic Escape), you may have it attack another player, attack a planeswalker an opponent controls, attack a battle an opponent protects, or not attack at all. If there's a cost with having that creature attack its owner, you aren't forced to pay that cost, so you may have it attack another player, attack a planeswalker an opponent controls, attack a battle an opponent protects, or not attack at all.