I would start off by having the students compare and contrast the Japanese and Chinese immigrant experience talking about the differences in the experiences of the two groups. I would remind them of the sources used in the previous discussion of the Chinese and also provide links to the Smithsonian Feature "A More Perfect Union", KQED's Feature on Japanese Immigration, and the material from the Columbia Basic Ethnic History project. If the students needed additional support I would have them look at the Immigration feature for the Chinese and Japanese communities to see if that provided any additional support.
As an additional discussion topic I would have the students look at the experience of those immigrating today either by adding additional readings or having the students do oral history interviews with today's immigrants. You can see a sample project on the Learning Page.
I might also have the students look at online exhibit on the Floating World of Ukiyo-e the and focus on the section looking at cross-fertilization between the west and Japan and its impact on this particular art form. This might lead to another discussion on how different cultures have played a role in United States and if these changes have been for the better or the worse.
I'm also wanting to bring some maps into this lesson. One favorite is this world map from 1858 which documents where different groups ended up in the United States. Another fun thing about this map is that it's in French so that the students won't have text to guide them but will have to look for visual clues that may help them. I also really enjoy using the National Atlases and these all have sections on immigration and where immigrants ended up. It might be interesting to compare the 1890 maps to the 1970 maps (the most recent we have online). The students can compare the maps and look for similarities and difference in immigration between 1890 and 1970 and see where groups settled in 1890 and where they settled in 1970 and could specifically focus on the Chinese and Japanese and see where they settled and why they chose these specific locations.