Well, my DD is almost 1 year old now, so I've had a good amount of experience with tandem nursing. :LOL I guess I should answer my own questions...
How soon does the milk come in after the NB is born?
it really depends on the woman, but mine came in about 2 days after she was born.
Does it come in a lot quicker than it normally does?
I think it did, because there was a lot more suckling going on than there would have been with just the one baby.
So will I really have enough milk for TWINS?
Sure did!!! Or even MORE
Will the colostrum get thick once the NB is born?
I don't really remember this one, but my baby was fine on what she was getting. I think the colostrum got a bit thicker after she was born.