Which is why I said...
"Android is designed to make you use Google services - not to coerce anyone, true, but the entire OS is geared towards this purpose, and that is the most likely practical outcome."
Not every Android user will use these services. But it is the obvious choice and most will take it, because the OS is designed for this purpose. There would have been no benefit to Google if it hadn't been.
And personally I would guess that the people designing the OLPC have no great incentive nor much ability to change the default Android install. They will add their own learning-oriented applications to it, sure, but a whole app store? Unlikely. Everyone needs basic applications like e.g. email, so will the OLPC folks go out of their way to include a very visible alternative to Gmail? Probably not, because there is no special learning purpose involved in email (apart from "being able to use email", clearly, but that's just one lesson). More likely the kids will end up using Gmail (assuming the village has at least one wifi access point, obviously, but if it doesn't then the whole project is severely handicapped anyway, regardless of whether Android is being used.)