Normally no. Reason, because being pregnant normally stops any further ovulation taking place.
Yes, you can but only in extremely rare cases. There have been 10 such cases reported in the US. A woman from Arkansas is currently going through this situation. Check out ABC.com for the story.
Yes you can, it doesnt really happen often, but one baby can be forming in the right place and another in the fallopian tubes.
That is the dumbest thing I have ever heard.... Your answer is NO YOUR ALREADY PREGNANT!