Because somebody put it on youtube doesn’t mean it’s free to use.
The federally-produced instructional film, you might get away with using, since it was taxpayer-funded and also might be old enough, that would probably (but we don’t know 100 percent) be in the Public Domain. A question would be, who put that footage up, where did THEY get it from, and do they have any claims on it? The footage might be public domain, see, but if the specific version is one where someone went to the trouble of cleaning and grading the footage, that version of it might have rights problems attached to it, the same way you can pretty much go crazy with a B&W print of “It’s a Wonderful Life”, but not the colorized Ted Turner version. Try the web site for BZ Rights and Permissions, see what you can find out there.
As to photos of those historic figures, the person who took the photos, or his estate, has the rights to them, or some concern like Getty Images may have bought the rights to that image, and you’d have to negotiate with them for the rights. The first thing you should look for, for those photos you want, is to see of there is a usable free image in the Creative Commons web archive, or in the Library of Congress.
Corporate videos have a long history of appropriating stuff they don’t own, on the theory that the video is for internal use only and will never be seen elsewhere.
Kind of like private, intimate photos and images made by Hollywood movie stars, hm.?
Everything gets out, eventually. The only questions are when, and what the repercussions will be.