Has your employer explained WHY everyone's hours have been cut to under 30/week? Slow business conditions perhaps? There obviously has to be a business reason - the company didn't do this on a whim.
An employer's policy stating that they consider those who work 32 or more hours per week to be full-time is not a guarantee that everyone will have that many hours. If this is a temporary reduction in hours due to slow business conditions, then it's unlikely you will lose your benefits. All the plan documents for group health plans that I've ever seen contain language to the effect that a temporary change in hours does not have an impact on an employee's eligibilty for participation.
Sounds like most of your questions need to be directed back to your employer. We don't know why your hours have been cut, how long it's going to last, or what impact it's going to have on your benefits, if any.