kbrn2002

If you are being asked for a reference as a manager many companies have a policy to only confirm start and end dates of employment and eligibility to be rehired so you could easily stick to that rule without raising any eyebrows. 
If you are being asked for a personal reference that is a little trickier to navigate. If you don't think you can in good conscience give a good reference I would find a way to respectfully decline.
If this co-worker then decides to use you as reference anyway, or if you are used a a reference without being asked for one then go ahead and give your honest assessment.

Of course rules and regulations vary from state to state so look at the expired license/renewal requirements for the state license you aren't using so you'll know what you need to do if you ever need to reactivate your license in that state, it will be on their BON website somewhere.  
 I was licensed in 2 states and wasn't using my secondary license so I just let it expire. About 2 years later it turned out I was going to use it again and I just had to pay a small renewal fee.  

Let them spout their empty threats if you stay at this job.  It's not abandonment unless and until you accept your assignment. If you left after you initiated your shift and also assumed care of the patients then it's abandonment.  Not answering a phone when they decide you are on call, without actually paying you to be on call is definitely not. Though honestly when an employer starts spouting the "I'll turn you into state" threats that's about the time to get out of Dodge. 

This question requires a two part calculation to get to the right answer.  You first need to determine the length of time in minutes to achieve the ordered dose without exceeding the maximum mg/min which appears to be the step you completed.  However there is another step to determine the answer the question is actually asking for.  Once you had the max mg/min calculated  you then need to do the conversion to get the ml/hr final answer the question is asking