False! Alt H will hide selected sub-object selections. As for your scroll wheel problem... installed any scripts recently? Edit Edit wasn't needed, I failed to read.
If for input you have only this 2 textures you should select the black color on the rock texture and use this selection as a mask. You are unable to do any magic tricks here.
In case you need to use Max later... I would pass a sub-object selection up to the Displace modifier. I'd also use soft selection if it needed a transition area.
W+right click > Axis > Custom > Set to edge > Select one edge It's possible that it's called "Set to component". What this does is that it aligns your manipulator to the selected edge/face/vertex.
Tint the shadows with red in the AO map for starters (create a Selective Color -adjustment layer in Photoshop, select "Black" from the drop down menu and set red to something like +15).
In Maya, you can check some topology like you want using selection constraints ( it allows you to select by triangles, ngons, and a whole list of other options. Really useful.)
In Houdini I can paint selection and just force this selected polygons to have cusped normals. Or do this procedurally. I think in 3dsmax you could use Edit Normals Modifier.
there is also the layer system, you can use the number keys or select a layer from the bottom toolbar, and use hte m key to change what layer the currently selected objects are on.
Should be able to right click > Open with > Choose default program... > Select Maya 2014 exe and make sure you tick "Always use the selected program to open this kind of file".
Appreciate the help, seems the functionality is slightly different, I found an option to select by color which picked up the UV layer lines that were in the layer and let me stroke the selection.