1; yes you can tansfer but first of all you have to get LOA from U of S or A and then you have to submit file or application at vergiville office (alberta) so that they can change the institution name on your study permit only if
you are changing your study level as well like changing degree level while changing your school.
see the following it will definitely give your que's answer: http://www.cic.gc.ca/english/information/faq/study/index.asp
at the aforesaid link there is question:
question:I am already in Canada and have a valid study permit. I would like to change my school or program of studies. What do I need to do to modify my study permit?
answer:If you are changing schools and/or your program of study but remain at the same level (e.g., secondary level), you do not need to modify your study permit.
However, if for example you are a student at the primary school level and you are moving on to secondary school, or if you are a secondary school student and you are moving on to post-secondary studies, or if you are moving from post-secondary studies to secondary studies, you need to submit an application to modify your study permit at the Citizenship and Immigration Canada Case Processing Centre in Vegreville, Alberta.
NOW COMING TO YOUR 2ND QUESTION:
I am giving your a link which will directly take you to your dilemma's solution:here is written your eligibility for applying for SINP program depending on degree that you are applying for and when you can apply.http://www.saskimmigrationcanada.ca/student
So here you go now your 3rd question:
it does not matter where you study and where get job but yes the place does matter for applying for PR like if you get job in ALberta then you have to apply for PR in Alberta for which there is another link which I have written at the bottom of this paragraph.The difference between AINP and SINP is that For SINP you can apply for any FULL TIME
job even it does NOT
relate with your study which you have done in Canadian post secondary institution but for AINP there is specificity for FULL TIME JOB
job which recommended to be related to your studies and MUST be one of NOC O,A or B job which you can find at given below link and yes,there is specificity for hours of PAID JOB WORK EXPERIENCE too BEFORE YOU
become eligible for applying for PR in both of these nominee programs like For SINP you must have to complete 960 hours of work experience(paid job) BEFORE
applying for PR which may include your on campus or off campus job.http://www.albertacanada.com/immigration/immigrating/ainp-eds-international-graduate-criteria.aspx
I THINK I HAVE GIVEN YOU ENOUGH INFORMATION that YOU ARE SEARCHING FOR!
please let me know if any other info you need