Hi hermytm,
Unless they are hand-crafted one-off articles, manufactured toys are not ordinarily subject to copyright. They may be subject to various other forms of intellectual property rights, such as design right, or trade mark, but neither of these (or for that matter, patent, which could apply to toys like Lego or Meccano etc) would be infringed merely by photographing the toys.
The fact that these items are in a museum may indicate that some of them (for instance early prototypes or design models) could be subject to the hand-crafted exception, if they qualify as works of artistic craftsmanship. It might be best to check with the museum. You will also need to check with the museum over its policy on filming of the exhibits, although of course that has nothing to do with copyright.
If you think copyright might apply to some or all of the exhibits, it will last for 70 years from the end of the year in which the person who created it died. You mention fair use. If you are based in the USA (where the fair use doctrine applies) then it is more than possible that this would cover your filming, if the toys concerned did appear to be protected by copyright, as this use would clearly be transformative and would not economically threaten the market for the toys themselves. But there is no corresponding exception under the UK's fair dealing exceptions. The nearest we have here would be
section 30, for the purpose of criticism or review. You would need to examine the purpose of your film and if, as it appears from your description, it could be argued that that was its purpose, then this exception might well allow you to go ahead, but you would need to acknowledge all the copyright owners (ie the manufacturers), probably in the credits of the film, so it would be almost as onerous as contacting them for permission in the first place. There is a
second exception, where something is included in, say, a film, in an incidental or passing manner, but I don't think this will be much use to you as it would appear that the intention is that the film will feature the toys, and thus their inclusion would not be incidental.