Can you show a video or GIF of what happens after you click 3 times? If you click the first vertex to close the mesh hull then it will end using the New tool.
Note there is also the Trace button on the mesh edit dialog that was added after that video was created.
For the other issue, select a bone to be the parent, hold cmd, click one or more attachments, release cmd, then click or drag to create a new bone. The attachments will move under that bone.
Both of these are working when I tried them. What version of Spine are you using?
