1) 7.5 bands are required to get study visa in any college of REGINA.
Probably but if you can't get 7.5, talk to the college you want to study at, they can tell you if they accept less. You don't have to qualify for all colleges when you only want to study at one.
2) 1 year full-time job can make one eligible for PR in Saskatchewan.
Not necessarily so. You have to look at the different immigration classes at
http://www.saskimmigrationcanada.ca/sinpFor the skilled worker class, see
http://www.saskimmigrationcanada.ca/skilled you can apply if you are outside Canada and have a skilled job offer or if you are on a work permit, have worked for 6 months in either a skilled job or one of their other jobs they allow.
For the student class, see
http://www.saskimmigrationcanada.ca/student you can apply if you have at least a 1 year course and you have worked for 960 hours and you have a job offer.
3) One must have relative in Saskatchewan to get approval of SINP.
Only if you are trying for family class, see
http://www.saskimmigrationcanada.ca/family-members4) SINP processing time is 10 months.
Is it? I have heard it takes only 3 months to get a nomination but that is not including the time it takes to get the PR. You have to look at
http://www.cic.gc.ca/english/information/times/perm/provincial.asp to see the processing time for provincial nominee PR in your homeland.
5) Work permit must be long enough to sustain in Saskatchewan until one gets her/his SINP approval.
Yes. If you do a one year study, you get a 1 year open work permit. That should be enough to get nominated. After you get nominated, you will not need a labour market opinion to get a regular work permit.
6) One can not issue Spousal open work permit based on her/his spouse's study permit
If you are on a study permit, your spouse can certainly apply for an open work permit but still has to prove they will not overstay. Once you get a post grad work permit, your spouse can only get an open permit if your job is skilled.