How to get collapse text to open below admin menu?
This is a CSS issue; what you need is to move the named anchors up a bit for administrators.

Here's a sample code:

/* If you are using the core Toolbar module. */
body.toolbar a[name],
/* If you are using the contrib Administration Menu module. */
body.admin-menu a[name] {
  position: relative;
  display: block;
  visibility: hidden;
  /* This value will be different for Toolbar/Administration Menu modules. */
  top: -30px;
}