I think it's pretty much safe to say that all current flagships and last years flagship models will receive Android "L", whatever the name may be called, unless there's a reason not to update those devices.
If I have an unlocked AT&T phone, can I install Lollipop from LG or from Google? Would either LG or Google offer a version for installation to end users? I would not expect LG to offer anything except for model-specific updates. But Google? Probably not, also.