The original discussion is at https://forums.xamarin.com/discussion/24845/linkassemblies-task-failed-unexpectedly and I posted a comment there. Since it seems stale, I thought I should open a new question here.
I have done all of this (Link All + min/target version) and it compiles and packages fine. That would work well if I were not targeting Android 4.4.2. I sideload the app onto my Android 4.4.2 tablet and it installs fine. It then stops when I try to load it. I am using HorizontalScrollView, so I need Xamarin.Forms - correct? Do I have to install only on Android 5 and above for this to work?