Hi @ana93 glad to hear we are surpassing your expectations ;) yeah it’s great having all of you on the course, sharing your knowledge and experience. I like your sequence of activities, but the only thing I would suggest is to follow the test-teach-test model, where students start with writing three sentences (one for arise, one for occur and one for happen). This would be also helpful because they can compare their sentences to see what nouns they used for subjects, as opposed to brainstorming for subjects that collocate with these three verbs. Then, there is the teach stage where they are introduced to WSD and do tasks you described. Finally, in the test stage they can go back to their sentences and correct/revise them themselves or do peer correction/feedback. This leaves the teachers with a set of sentences before and after being introduced to the tool and the opportunity to evaluate how effectively students have edited their sentences. By the way, if your colleague is going to use WSD without any prior exposure to SE or corpus tools in general, they might need some scaffolding or guidance from you ;)
By the way, you could tell me a little more about what kind of word bank for exams you are looking?