If anyone is still looking for a way to do outlines and drop shadows with runtime fonts for use with Slate and UMG, please see my workaround here (which was implemented in 4.8 and requires one engine CPP file change):
Here’s an example of it in action - two runtime Slate fonts using outline + drop shadow:
https://forums.unrealengine.com/attachment.php?attachmentid=48338&d=1437093579