Is it possible to cancel and "non-cancelable" order and recover my down payment if I am dissatisfied with a company's service?

A reliable answer cannot be provided without seeing the contract.

Is it legal for a supervisor to send an email out to the whole department that I'm on a leave?

there is no legal claim based on the information you provided.

You can be let go for any reason or no reason. It does not appear that you have a factual basis for legal action.

Is this legal and should I consult an attorney.?

I agree with the prior answers. Let the union handle it.

Guess question is someone would have had to ask them to come in (employees) right?

Unions don't have to be asked to come in. Union organizers can approach employees.

Is scheduling based on tenure in a position legal?

I agree with the prior answers. There's nothing illegal about scheduling based on tenure.

Where do I go from here

You should consider starting with the Department of Labor.

Would this be a good ADA or discrimination case?

If you can prove your employer is holding you back because of a disability then you have a case. The other job, though, seems like a realistic option.

I was terminated from my job for budget cut and so called attendance. Is my ex-boss aloud to disclose the reason to other employ

There's no law that prevents an employer from disclosing the reasons for a termination, as long as the disclosure is truthful.

I know this is windy but should I pursue getting an attorney for violation of the ADA laws? Does this quality as a violation?

Call a local attorney and retain him/her to challenge the employer's decision.