If you want the disconnected effect of the first technique but also want the strength of the second, then lining or partial lining is your friend. After cutting the garment apart along the desired lines, finish the fabric with either an overlocked edge or a tiny hemmed edge. For a frayed effect, run the edge between the nails on your thumb and index finger to separate the fibers, and then use Fray Check. If the fabric is polyester, you can even burn the edge because the fibers will fuse together. Do this in an area with proper ventilation since burning plastic does give off some nasty, hazardous fumes.
If you are using lining, then pin the two sides in place (here’s where you get to decide how much space you want between the two pieces of fabric) and with thread matching the top layer of fabric, stitch very close to the cut edge so that the seam is nearly invisible. On the other hand, if you are using a partial lining or just an insert of fabric underneath the seam, first determine if the insert can be seen through the top layer of fabric. Once you’ve determined that it cannot, then make sure that this layer is securely pinned in place as well as the top layers, as described above.
After this, proceed to use your preferred ‘thread’ for the oversized stitches. I like narrow bias tape because it looks finished and its lies flat well. Just make sure to use Fray Check or a similar product on the holes you create for the ‘thread’ if there aren’t grommets, so that the garment doesn’t become any more distressed than it needs to be!