And I was able to get an answer that, no, one can't embed a Seesaw activity. One can link the Seesaw app with the redirect, and kids can do the work there but they can't do the activity within Canvas.
Honestly, I'm just curious as to why you'd want to. Do you need to use both? Can you just have the students complete their work in Seesaw and share it directly with parents that way? I just feel both were pretty much created for the same purpose. And Seesaw is definitely more child friendly than Canvas is.
Our District is requesting all staff use Canvas. Some can use Seesaw, primary grades. We were trying to find a way to integrate the power of both platforms. Students can learn how to copy and paste the URL into Canvas, even the little ones with time and practice but it would have been nice if that did not have to happen. Like many others, we are figuring things out. I appreciate this forum to be able to get ideas, feedback and answers!