You should report this matter immediately to your employer and speak to an attorney who is familiar with both Texas Workers' Compensation as well as personal injury claims. If you were entering the premises in the location you were supposed to entering and exiting and were not on a personal errand at the time, I do believe you very well may have a Workers' Compensation claim. Assuming your employer is a subscriber to Texas Workers' Compensation insurance. (Not every employer is)....
This is a difficult question to answer without knowing a bit more. Generally your car is worth what it is worth, not what it's worth to you so you may want to check the value online with sights like kbb.com and also see if you can find some for sale in the area that would give you a replacement value. Also you should be able to recover you damages; i.e. lost time from work and medical expenses. I would be concerned about this driver being excluded, but if he works for them this is probably...
It does not appear there is either an injury or a damage in this case. If there were no injury, then for what reason would you file a lawsuit. If there were no damages, then what would you hope to recover. However; it sounds like an uncomfortable and unfortunate series of events.
The answer to this question would depend on why your wife came to be injured. I would speak with an attorney in Florida to discuss the facts and allow them to make a proper determination of your wife's rights.
In my view the liability would be on your friend and not you. I fail to see how you are liable for any damages caused by the actions of your friend. Was he driving your car at the time? If so then you should report this to your liability carrier as soon as possible.
Consult a medical malpractice attorney as soon as possible. You very well may have a case but due to the specialization of medical malpractice in Texas it would best be left to a specialized attorney to determine whether you truly have a claim.
You can always change your attorney; however, if you signed a contract you may have problem finding another attorney as the first attorney will have an interest in your case and will seek to enforce that interest meaning your second attorney may not be paid as much or anything for the work he did.