What do I need to do to make the following flow to update a field on several member records with user input?

To allow users to add commentary to multiple campaign members at once, I'd like to do the following, starting by clicking a button on a campaign page. Please let me know where I'm doing something wrong. Also, if we could speak on the phone, it would be super helpful. Thanks.

1. Screen: Show multi-select checkboxes of a dynamic record choice based on campaign members that meet certain criteria.
2. Fast Lookup: Lookup all campaign members that were selected. (Do I save in an sobject variable? Or an sobject collection variable?)
3. Screen: Display the name of each campaign member from (2) along with the existing notes, along with a text box to allow user entry. (How do I get the pattern Campaign Member, Campaign Member Field, Text Box and then get it to repeat?)
4. Assignment: Change the sobject variable or collection from (2) by appending the user entry from (3).
5. Fast update all records from the newly assigned variable. 
6. Show an error message if someone else updates at the same time
7. Say thank you.