IELTS

6 band in IELTS is not enough to get a student visa. I can suggest universities which accept 6 band and you can get admission successfully, but your visa will get rejected which means you will lose the admission fee for the first semester as you can't fly to Canada. So reappear for IELTS exam and aim to score at least 6.5 band or above.

Hi
The best way is to check a mock test available online and attempt it as different people have different abilities. Also, it depends on your instructional language to know your proficiency levels.

You need to appear only in GRE and IELTS for the same.

You need 6.5 bands in IELTS for a good college.

Yes, you can apply for January, 2017.

No, you cannot get admission. You should reappear for the IELTS test.

For visa, your marks are not considered. Your motive of visit and aim plays the important role.

IELTS or English language proficiency test is required in the UK. You must write to the universities if you are planning not to take any test. It is very rare that they accept candidates without an IELTS score. Visa rejection chances are also going to be high.

Yes, you can. Apply online or get assistance from a study abroad consultant.