I always hate searching for info on google, finding forum posts that basically have the same problem I have and then there is no solution! Ok, maybe you don't need this anymore as it's been 3 years but I'll respond anyways for the record.
I opened up KMUO in ADE to see all the stuff that's been placed. You have to open the bgl file of the airport and then import the bgl file of the objects that is in the same ORBX folder.
(In the ORBX folder called FTX_NA_CRM05_SCENERY/scenery, import the airport from bgl into ADE with the file ADE_FTX_CRM_KMUO_Mountain_Home_AFB.BGL and then do an import bgl in ADE with the file FTX_CRM_objects_KMUO_PLC.bgl. Don't do anything with the file ADE_FTX_CRM_KMUO_Mountain_Home_AFB_CVX.bgl)
Once you have all the objects and the airport, I clicked on the static jets and found the unique ID for that library item. I copied and pasted it into notepad.
Now, I have about one solid day of figuring all this out with ADE so maybe there is a cleaner way but this worked for me. I had troubles other ways because I couldn't find certain library objects and couldn't recompile a bgl with all the stuff I needed. This is probably when someone else will jump in with the actual easier and proper way to do this.
Ok, back to the process. Once you have the unique ID, I decompiled the file FTX_CRM_objects_KMUO_PLC.bgl into an XML file using something like bgl2xml. I then did a find on every instance of that unique ID in the xml and deleted the scenery object section. Repeat until they are all gone. Save the xml and then recompile it back into a bgl. Replace the old file with this new one. I like to add .OFF to the old file so I have a copy of the original as designed by ORBX.
That should be it. You can use this method for any airport. I removed a bunch of B52s from Travis AFB using this as well. Hope this helped, 3 years later, or hoped it helped someone else!
As for replacing the scenery totally, take a look at this post. Holger has released a patch/exclusion file that surpasses ORBX KMUO buildings when replacing with a different version of the airport. I have mine dialed in now and I'm about to go try this path though to see if I'm missing anything by having the ORBX airport completely turned off. Before I saw this, however, I had to disable the ORBX KMUO airport completely in order for the duplicate buildings to go away. Simply loading the new airport first didn't exclude them from showing up.