Columbia Student

Hi all,

I am an Indian in the last semester at Columbia Univ and got a change
of status from H4 to F1 but have not yet gotten it stamped. My
questions are:
1) is it advisable to travel to Canada to get my visa stamped in the
last semester
2) the H4 visa on my passport expires on Jan 12th. does this date
matter in terms of whether I should get an appointment before or after
this date
3) if my F1 is rejected is my H4 also rejected or can I come back on my
H4 and seek a renewal of the H4

Thanks in advance for your advice.