I assume you already have gotten PGWP ?
for MPNP you can only apply after 1 year if you study from any other province than MB.+ Processing time (couldn't find it)
International students from other provinces: If you want to apply to the MPNP because you've been offered a job in Manitoba, note that to be eligible you must first have been working for that Manitoba employer for at least one year.
http://www.immigratemanitoba.com/apply-to-mpnp/mpnp-eligibility/manitoba-employment/#working-grad
If you put in your application & your WP expires. you will have to maintain legal status to stay in country as visitor/student. if you don't you will have to leave country after expiry as mentioned on PGWP. if you get Student/Visitor doesn't guarantee they will process your application, it depends from province to province some do some don't. you can call all of them and find out. i know AB doesn't.
Employment rate you can check here http://www.jobbank.gc.ca/home-eng.do?lang=eng
this will tell you jobs, median wage, etc.
I'm not sure what's your main goal here, PR or make money and go home.
for Nomination I don't recommend anyone AB they've more 9000 applications to process with only 5500 nominations to issue. so you can imagine which year they'll open your file. I've applied in DEC 2013 haven't heard anything yet.
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If you haven't gotten PGWP i would recommend everyone to study at least 1.5 to 2 year this will buy you more time when you apply for nomination. but even this also won't help in AB because Processing time here is around 25 months which is absurd. (REMEMBER YOU ONLY GET 1 PGWP NOT MULTIPLE)
I think your best bet would be BC or SK. but call all of them and find out all your answers before moving anywhere.
Good Luck