Work release is administered by the Department of Corrections and not part of the plea deal, however, the judge can recommend it to corrections. The problem is that eligibility for work release depends on your custody level, and armed robbery is a violent crime. Talk to your jail counselor.
I sympathize with you, however, unfortunately the medical malpractice laws do not encompass what you described. The medical lobby for years has been painting attorneys as these money grabbers that only care about how much money they can make, when in reality it is the low performance of medical professionals that opens the door to so many lawsuits. In your case, for example, it will be almost impossible to find a medical professional that would certify that the treatment you received was...
What you should really do is hire counsel. Contacting a witness could be perceived as a crime itself (tampering with a witness), so I would suggest you do not attempt that. Your story sounds like you have made a few mistakes, you should start doing things right and the first step is to hire a competent criminal defense attorney. Good luck.
The age difference will not be a problem per se, however it will probably trigger a higher degree of scrutiny. If your marriage is for love and not just for immigration benefits, you have nothing to fear. However, do not do this on your own! Hire an attorney to make the process smoother.
Your half sister is still your sister, there is no discrimination for half siblings, so yes, you can petition for her if all the other requirements are met. The fact that your mother died when you were little does not change anything. However, waiting times for siblings are very long, so you should be patient to reunite with your sister.
I am assuming you are not Cuban yourself. If your Cuban husband obtained his GC as a CU6 then you should not have any problem, just send your I-485 (no I-864, as this is not a petition). However, recent BIA decisions may impact your ability to adjust status if he is not CU6. Consult an Immigration attorney as this is not a simple matter.
Unfortunately, you have to wait for your I360 to be approved to be able to adjust your status. You mentioned that you had an EAD that was expiring; you could request an extension of your EAD based on your original grounds. You should definitely consult with an immigration attorney.