For the specific questions brought up here I'd suggest contacting the Thailand Elite office (TPC). As I understand there should be no problem with any of what you've outlined but they would be able to explain the mechanics of it. TPC is a membership that includes a visa (rather than a visa per se), and that membership doesn't expire if it's temporarily interrupted by switching to another visa class that allows for employment, rather it's just put on hold for a time. Not sure whether this would also apply to the other privileges such as airport fast track, limos etc.