For a hotel, there shouldn't be an additional charge for kids. For a plane (duh) there would be. Most hotels put the rooms blocked for these groups in under "Hotel Reservation Network" or whoever it is and then change the name to the guest's name once they have a guest. I'm not sure how WDW does it, but I can't really see it being done any other way.
All of your paperwork will have YOUR name on it.
Unless they go out of business, they are trustworthy.

When all this online stuff started, lots of companies signed up to do it, took the money from the customers, never paid the hotels...and went out of business. Many folks got stranded in strange cities without a hotel or the money to pay for it.
The scam artists are now pretty much out of the way. Expedia and Travelocity aren't scam artists. But, I don't know what their P&L looks like or if they're ready to file for bankruptcy or whatever - can't make any promises.
All that said, I would use them if they gave me the best deals.

Have used them.
