There are more steps after the screenshot I showed you; in total it's five emails and four 'request campaign' steps (with wait steps separating them out). Because they haven't received email 3 in the flow and are in the wait step until tomorrow, aborting is I think all I can do.
Everyone is in the wait step at the moment, but will the send will start processing tomorrow.
Sure! You can also just run the "Remove from Flow" flow step on all people in the campaign, so they get removed from it. You can then have the first flow step that people currently haven't flowed through in the existing campaign as the first flow step in your updated/new campaign. Let us know if you have questions. 🙂