No, you can not use “for” in place of the phrase “instead of”because it means; inplace of, rather than: I ordered chicken instead of fish.
The preposition ‘for’ means : In favour of, intended for, in the direction of and many other uses. This is for you.
Your e-mail is Ok. I have made a few minor modifications as belew:
I like to take a quiz instead of doing research.
Do I have to go to your office and read the article in limited time for takingthe quiz right after reading or am I supposed to read the material at home and then take the quiz at reserved time?"