I believe we have found a solution to our problem. We were able to reduce the package size a couple of different ways depending on what version of UE4 we were using.
In 4.25 we disabled all plugins were knew for sure we were not using.For some reason this caused the project not to be able to be built in windows for iOS, even though it is a blueprints only project. We have hooked up a mac and are doing remote builds.
In 4.24 disabling the plugins didn’t seem to have the same impact. The package size only reduced after disabling both “fast math” options (“intrinsics” and “optimisations” as listed in the iOS project settings).
With both of those done, the project went from 400MB to 70MB even with our core gameplay code and artwork. There is another 40MB that can be recovered if you aren’t using bloom in your game by removing the bloom material the engine includes, but we are planning to use the effect and have left it in.