I really like this lesson plan. I think that it is very well thought out in design. I like that the students are working together in groups face to face as well as collaborating online. I think that this will help the students make more mearningful connections. It will also help them learn together about online resources that will be helpful to them in the future.
One thing that I think you should include in the plan is an overview of what diingo is. I have an idea but others may not be familiar with what it is or how to use it for their classrooms. I think if you could give a basic overview about diingo and its features it would make using this lesson easier.
Another thing that I think would be beneficial to the students is for them to share the information they have learned with each other. I think that they should be required to look over so many projects and comment on them or else have them do some sort of presentation so that the other students can learn from each of the group.
I would include the link to diingo in the lesson plan so that it is easier to access the site. This way you can just click on the hyperlink and be taken directly to where you need to be. I think it could save time while working on the project.