Marvelous Designer is an application for creating 3d clothing. It actually works the same way as sewing, as you lay out clothing patterns, and stitch them together. You just do it in 3d in this case. It's a great application that's able to get results comparable to sculpting in zBrush, but it works very different than any other 3d application.
For textures, I'd start with Photoshop. That's the best way to learn to work with UV's and layout your textures in 2d space. From there I like working with zBrush and Substance Painter. Both are on the shortlist for any game developers desired skills. They actually work pretty similarly, in a way at least. The textures baked in zBrush and Substance Painter will require a bit extra work though for FF7, since they'll greatly depend on normal, specular, and ambient occlusion maps. For FF7 alone, Photoshop is your friend.