Java – the ideal learning path to building Android apps with Scala, without prior Java experience

For simple apps/games? I suggest you use what you're familiar with. Since you said you're familiar with all of those technologies, I would suggest the Android SDK in Java. Here's why:

• C# for Monodroid is a pay-for product and the future of Mono is currently unstable for a bit. Although this would be the fastest if you're a C# developer, you don't give enough info to say you're better at C# than Java, so stick with Java.
• Phonegap and Appcelerator don't give you total control over everything. If you're writing games you know how important it is to have as much control as possible.
• Adobe Air is in the same boat as Mono, except much worse. Adobe air requires your user to download Adobe Air as a separate application, and keep it updated. Using the native SDK gives your user an overall best experience, and you'll have much more community support as a developer, not to mention the treasure trove of resources at http://developer.android.com

I think the discussion regarding objects vs. functions is a red herring. If the question is, "Is a lambda a function or an object?" the answer should be yes.

That's the point of first-class functions: they aren't treated differently than any other type. Java already manages to mostly ignore the differences between Object and primitive types (and Scala does even better), so whether a lambda is a subclass of Object or is a new primitive type or something else isn't really important for the language. What is important is that you can put your lambdas in collections, pass them around to be called, call them, and do anything else you might want to do with either an object or a method.

Scala accomplishes this by using a wrapper object that has a method called apply which can be invoked with just (), making it look just like a method call. This works splendidly; much of the time you don't need to even care whether you have a method or are calling the apply of a function object.