I think somebody cursed us with "May you live in interesting times!" We certainly are. Without giving legal advice here are some answers to common questions in putting a class online very quickly.
Remember that you do not need to meet all factors of the fair use checklist, the descriptive page at the beginning is a good description of the analysis.
Video online is a bit harder because you have to consider not only fair use but the Digital Milenium Copyright Act. This last act prohibits any digital protections put on recordings such as DVDs. Most DVDs do not allow copying. Even if you wanted to use a small amount and felt it was fair use, you can't record that small part off of the DVD to put online.
Try to use video from one of our streaming video sources.
Note that this is not legal advice but I would say that you can provide access to materials owned but inaccessible through a password-controlled medium (D2L) for a limited time. What I mean by that is that the students would need to log in to get the items so D2L is a great place for them. At the end of the semester, you should make sure to not only inactivate your class but to delete those materials you added for this emergency situation. Technically, this use most likely falls under fair use, but making a blanket statement like this isn't allowing for analysis of each situation. If you are unsure, use fair use!
Fair use may allow you to use images. The problem with images is that fair use allows for use of a small portion of a work and, in many cases, you want a large portion or the whole image. Fair use does not require that all factors are in your favor so your use may still be a fair use. My recommendation (without this being legal advice), is that you make sure you cite your images well (you are being a model of not plagiarizing material) and that you make sure your PowerPoint can only be accessed by your students. Put the PowerPoint on D2L and you might put a warning on it that is should not be shared outside the class.