Boxes in a sequence questions

The default Sequence quiz question is quite limited in formatting options.

If you want something more similar to what you have illustrated on the second screenshot above, you might be better off thinking in terms of a Drag and Drop slide where the target objects are numbered and your student needs to drag the rectangle objects to their correct sequence location.  

Drag and drop slides can be set to report to the quiz in much the same way as quiz slides but there are some limitations in terms of getting them to behave exactly the same way.  It's up to you how important the appearance of the slide is.  You will have to compromise in some area no matter which way you go.

Pretty new to quizzes? 

Quiz slides are based on quizzing master slides, which have a lot of embedded objects to which the functionality of the quizzes is linked: submit process, appearance of the feedback messages, resetting, reviewing.... You need to keep all those embedded objects.

You can tweak the design of the quizzing master slides however, once you understand how they are set up. This is a lot harder when working with a fluid boxes project. From your screenshot I suspect that is not the case.

Try to edit the master slide for sequence questions which is the same as for MCQ and T/F. It may be better to duplicate that master slide and edit the duplicate to be used only for the sequence slides. Know that all custom objects added to a quiz slide will be below the embedded objects.

Alternative is with a Drag&Drop slide but it will not be easy to recreate all the functionality of the normal quiz slides: no Review will be possible.