The shared line appearance on every ext. tab needs to be set to private as well, only the phones main ext. should be shared.
The shared call app should be set to private for every Line Key except your main number for the phone.
I've tried this combo before and it doesn't seem to work. From my experiences the SD actually makes another phone call to the user that you are trying to CP, therefore adding two calls to one device. Seems that you can only have SD or CP, but the BLF works great.
This one works every time.
The orange buttons probably mean your Ext. 1 tab isn't configured properly. Remember to leave that one shared on the dedicated phone so the other phones can see it.