I have an NOC from my previous sponsor but then again, it won't do you no good.

The NOC should be in the company's letter head paper :)

I don't know about your sis-in-laws company...but she's too young to work. I wouldn't even hire her even if she's qualified....no offense meant.

If she came here under family visit visa, you must've have given them a No Objection for her to work and transfer her sponsorship to them....did you not?