This might not answer your question specifically but heres a few links that might be helpful as a former unity developer myself.
https://wiki.unrealengine.com/Transitioning_from_Unity_to_UE4
https://wiki.unrealengine.com/Unity3D_Developer's_Guide_to_Unreal_Engine_4
https://wiki.unrealengine.com/HUD:_Unity_3D_OnGUI_Remake
Plus someone is working on a plugin to allow you to code in C#
Also this How can I pass data from one level to the next? - Programming & Scripting - Unreal Engine Forums