Venomoose

In the US there are far fewer masters programs for chemistry than PhD programs. It is usually fairly rare to find a masters program for hard sciences (as opposed to engineering where it is far more common). My impression of a masters in chemistry is that it does not have much utility and is not particularly useful career-wise, but others may feel differently about that. In any case, as far as ease of acceptance I can only comment on engineering masters, which are much less selective than PhD programs. Most schools look at masters students as easy money and are happy to accept many international students.

I applied for the Fall 2016 admissions cycle and am smack in the middle of my visitation weekends at some schools comparable to your dream schools. Generally speaking it is absolutely not necessary to come from a very prestigious undergrad institution, and in fact many of the people accepted to top universities come from state schools or small liberal arts schools. I'd say if you have a competitive GPA (3.7+) and GRE scores you have a very good shot at all of your dream schools. Three JACS papers is quite impressive and should put you in a good spot.

The interview was related to the application process. One of my POIs cold called me to ask about my research interests/reason for wanting to attend Berkeley, and also spent some time telling me about his research. He said that they were calling some other candidates that they were interested in for interviews before they made their decisions. I'm not sure how many people they reached out to though or what bearing it had on my admission.

I heard back from Berkeley on the 21st directly from a PI that had interviewed me and has connections to my current PI. He said he was letting me know because the paperwork likely wouldn't go through before early January when official acceptances were happening. So if you haven't heard anything that doesn't necessarily mean you aren't going to get in. They also tend to accept in waves so even if you don't hear anything in early January there is still a chance (albeit a lower one) that you will be accepted. Also to raybans7, I was in a similar position to you and was still admitted so that may not be such a big deal.