Evaluate how to allow using FlyoutBase/MenuFlyout

[asklar]

FlyoutBase and MenuFlyout are not FrameworkElements (they're DOs); so the RNW API won't be able to create them
What can be done to enable non-FE DOs to be used/created in RNX?
One idea is to create a UserControl that mimics the properties on MenuFlyout and others, and copies those props to a wrapped MenuFlyout (and the UserControl has 0 measure).
That way the element can be created by the view manager and later on when AddChildren is called we can remove it from the tree, get the wrapped MenuFlyout, and attach it to the parent via the ContextFlyout or AttachedFlyout properties