Items in OmniFocus won’t repeat until they are completed or dropped.
As of OmniFocus 3.3 for iOS and 3.4 for Mac, the way that I would approach this is by keeping all of the steps in the same weekly repeating project, and then dropping the “spillover” steps once I had decided that I wasn’t going to do them this week (or once they became overdue). The if you set the project to “Complete with last action”, it should repeat as soon as you drop or complete the last child.
Another approach might be to put the strictly mandatory steps into a repeating project, and then stick the “cleanup” steps either into a separate repeating project, or as individually repeating actions in a single action list. You could apply a less strict repeat schedule (defer instead of due?) to them if appropriate.