Great to hear the E62 is already fixed! Sorry to waste your time about that one.
However I am confused about first. It is a property on CollectionType: https://developer.apple.com/library/ios/documentation/Swift/Reference/Swift_CollectionType_Protocol/index.html#//apple_ref/swift/intfp/CollectionType/s:vPs14CollectionType5firstGSqWx9Generator7Element__
If I try to use first() in Xcode I get:
error: invalid use of '()' to call a value of non-function type 'FooContainer?'
This would make it difficult to write code that interoperates with Fire. Is that intended behaviour?