If the morph works for the character, and the conformer fits the character closely, then it can "work" in the conformer just as well - that doesn't mean it will look natural though.  That's the problem with these extreme morphs like She-Freak and The Girl, they are so different from the base morph that fits have to be done by hand, which is an immense piece of work for high poly content with any detail on the mesh - and to make it worse, those morphs will never mix well when blended with other morphs.

If you are modeling for yourself, and you only need the garment to fit one specific morph, then it may not be a big problem.  If you want a garment that is flexible enough to look good on a wide variety of morphs (like buyers expect), then you have to compromise.  That's why I never bothered to add fitting morphs to the Demonatrix suit I did, because all the detail (the rings) just gets mashed, it looks terrible.

If you want to fit a very specific extreme morph that won't be mixed with other morphs, you can do what I did with the Seraphim outfit (before I knew better):  Model around the extreme morph, and then use something like Morphing Clothes in a backwards way, treat the morphed character as the base (export to OBJ) and make the default character's shape into a morph target for the new OBJ.  If it sounds terribly complicated, that's because it is; you end up (after a ton of painful work) with a garment that will only fit the morphed character, but it will fit pretty perfectly and will work with the rig.  However it won't work well with much of any other morphs, and won't even look good with the base character's shape!  I do not recommend this method unless you feel you have no choice.

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