It is possible to use Object Styles for positioning of Anchored Frames in a text frame.
Layers have no positioning!
Is this realted to your other question about repositioning master frames after they've been overridden?
If so, as Willi explained earlier, these are not a layer, simply overridden frames. He didn't go into a lot of detail about master frames behaviors, though, so maybe the following will help:
When you override a master object you lose the connection tot he master page for any attributes you subesequently edit. If you edit the text in the overridden frame, changes to text on the master page will not apply. If you override a master text frame before placing text, there will be no connection to any master text threading scheme. If you change the size or reposition the overridden frame, doing the same on the master page will have no effect on the overridden frame. And finally, master obejcts are always behind any live objects on the document page on any given layer, but if you use multiple layers you can have master objects on an upper layer that are in front of all objects on lower layers.