The best thing to do is to call the Copyright Office, go to their main web page and there is a phone number you can call to get to speak to an employee that can answer your questions. Yes, you will need to get permission from the copyright holder to use those photographs. Copyright lasts the entire life time of the person plus a certain amount of time after that. Unless your pictures fall into the "public domain" where copyright has expired you can’t publish the work without the permission of the original copyright holder.
As far as permission of the people in the pictures, the original photographer should have gotten a release for any person that is identifiable. You have to get permission of the copyright holder to use it and that probably is the actual photographer of the imaget, so I would assume that the release would extend if you get permission. I don’t think this applies if the picture is taken for "news related" purposes. This is the grey area where the tabloids get in trouble for publishing pictures of stars without their consent and often have to pay big bucks for the pictures.
Copyright is confusing, but it is not as bad as it seems when you read for hours at a time. I believe the site is www.copyright.org. If you google it, you will want to follow the link to the US Copyright Office. It probably is the first one that pops up.
If you go to the Copyright webpage there are lots of FAQs and good examples of items and if you are still confused calling them is often very helpful.