I think the performance objectives for this lesson are great. I love how you link the general to something specific to each student’s own family history and by creating digital artifacts you will add to potential source material for future historians. I also think it is great you include information on Angel Island as it seems to be oft forgotten in the shadow of Ellis Island.
Will you develop a set of questions for the students, will they develop questions on their own, or will you have them develop that collaboratively, perhaps with guidance from you?
One thing I worry about is how you accommodate students of Native-American or of mixed heritage, whether it is a fairly straightforward mix (say one side Italian-American and one side Laotian-American) or one that has been quite mixed up over the generations (for example, there is French-Canadian, English, Irish, Swiss, German and Native-American in my heritage that I know about).
There are links to YouTube videos which bring up several others on similar topics but also some unrelated videos. It might be good to have the specific videos you want students to watch embedded somewhere.