When using the Manufacturing Mobile app, is it possible to create a Work Order Completion from operating step 1 to another operating step but not the last one similar to the functionality in the regular UI?

Yes it is possible. You have to sign into the work center, then you should see your work order and operation. You complete it and then it moves to the next step and possibly work center if they are different. But it does depend on your set up as well. its not always the most straight forward process.