All of the above are valid steps to take in fitting.

I looked at Dylan and Ruffle Dress and these seem to have morphs in common, none should need to be added to dress.

One thing that people tend to overlook is to "magnetize" the outfit to V4.
These are in your pose folder and they unleash the underlying deformers built into V4 series.  They do wonders for most cases of poke-thru