Unless you signed a document authorizing deductions from your paycheck for damages, loss to the dealership or other costs directly caused by your work, they cannot take money from your paycheck. This is potentially a violation of the Maryland Wage Payment and Collection law. You should speak with an attorney to fully understand these deductions and whether or not you have any claims.
Your employer can choose to terminate you at any time. Giving a two week notice does not guarantee your job for the final two weeks. You are entitled to be paid any accrued leave time and other wages (bonuses, commissions, etc...) that you have earned prior to your last day.
In general, if you are an at will employee, your employer can change the terms and conditions of your employment at any time. However, the letter stating that your salary will never drop below a certain level is likely an enforceable agreement to maintain your salary at that level. Any change below that level may be a breach of contract. You should speak to an attorney to figure what your options may be to reinstate your minimum salary.
Employment in Maryland is at will, meaning you can be fired at any time for any reason. Unless your friend has a contract for a specific term or that entitles her to severance or some other compensation, her employer is free to terminate her employment at any time.
Are you required by some written company policy to give two weeks of notice prior to leaving your job? If so, you need to consult that policy and give your notice accordingly.
In any event, you should be paid your accrued vacation following your last day as an employee. You should not be required to forfeit leave time that you have earned while employed.
The answer to your question depends on what the new owners acquired when they purchased the company. If they simply acquired the stock of the old company, the non-compete might not be enforceable. If they acquired the assets, the non-compete would likely be included in that acquisition and may still be enforceable. There is still a question about whether the non-compete is enforceable at all, depending on the actual language and the proposes restrictions. You should have an attorney review...
Depending on the nature of your job and the frequency and duration of your call schedule, you may be entitled to payment for the time you were on call.
I urge you to contact an attorney to discuss whether or not you are entitled to any wages and/or overtime.
There is no reason that you cannot contact this person.
If he is violating a non-compete, you should act as quickly as possible to address that situation.
I urge you to contact an attorney to discuss your options to enforce your non-compete.
If your fiance is not exempt and is working more than 40 hours/week, she is entitled to overtime. Calling her a supervisor does not indicate whether or not she is exempt or non-exempt. An attorney will need to examine her job duties and responsibilities to help you make that determination. You should contact a lawyer as soon as possible to discuss this case.
Unless you have a contract securing your employment for a specific period of time, you are an at-will and can be fired at any time for any reason. Your employer can make unreasonable demands on you to finish work in a specific amount of time.