Yep, they are not expecting people to bring gifts unless they really want to (usually it`ll be family etc that still do).

Please get in touch and clarify about the childminding for you and them.
At my wedding we arranged childcare and specifically invited children by names on invites. The rsvps were returned indicating that children would be attending, so we went ahead with our plans to cater for the kiddies, and then on the day most of the parents left their kids at home , only for about half of those to make comments to us later in the day like " oh, little johnny would have loved this..."