Are you going to use geometry switching to add them?

No. I originally considered this, but I'll have to modify the joints, also. It may be possible to implement by means of a joint pose, but I think I'll just release a purely digitigrade version of the figure instead. If I do things properly, morphs and textures should be interchangeable. The clothing packs will need updates, though, to accomodate the modified legs and feet.

Can she wear any of the Vickie clothes without too much trouble?

Victoria 1-2? There's crumpling around the buttock/crotch region, and pokethrough around the hips and ankles. Sleeves don't fit particularly well. And I don't know what's happening with the neck. Proportions and joints simply don't match. Even if they did, you'd have to run everything through the Tailor, or create custom fitting morphs by some other means.

Short answer: trouble in River City. I can make things fit, but it takes effort.

On the other hand, Posette's clothes are a closer match, proportion- and joint-wise. Those could be adapted with much less effort.