Yes. You can access all the wizards with a free account. The only wizard not available with a Free account is a custom video wizard. To use a custom video you need a Pro (power and business) Account.
No. All videos create with a Free account will automatically be clipped after one minute. Once you upgrade to a Pro (power and business) Account your projects will automatically be reverted to their full-lengths.
You can move to a completed step of your project at any time, using the number buttons on bar at the top of your project. All the completed steps are shown with a filled green circle and current step is shown with a filled yellow circle. Uncompleted...
You can change your project’s theme from Themes Screen while creating a New Project on Editing a project. You can select any of the available theme showing on Themes Screen for your video.