Holy crapoli! Kat that is just shocking! I can not imagine. I think you need statistics. What are the chances of all four babies being healthy vs two babies? Also find out about your health as well. You have come so far to have a tragedy. Find out how risky SR is as well. Do not make a final decision until you have all those stats. It will be tough either way.
In a way, it would be easier for me having lupus, I would have to reduce. My immune issues and high blood pressure would not allow me to safely carry four.
Its awful to find out so late and be told you have two weeks to decide! It definitely sounds like you are thinking about trying to keep all four! If so, definitely find a way to be able to take it easy and give you body all you can so it can grow those babies.
I would also consider a second opinion. You definitely want to know the risks of two vs four up front. When looking at the number, you can DH can decide if the risk of keeping all four is something you think you can take knowing there is some risk of the babies having problems

I just do not know what those numbers are for the babies...
I totally feel for you, this must be awful for you right now. Esp since you know the sex for all the babies! You have to already be attached. I think you are just one week behind me now and I would just freak if they said I had two in there! But seriously, do what you think is best for you healthwise and emotionally.
I know for me, I would need to reduce and give the remaining babies and my body the best chance, but you do not have the same health issues I have (at least I do not think you do).
OH...can you do a CVS on the babies. I just had a CVS at 11 weeks. They say CVS is not really more risky any more than amnio if you have a good doctor. I am not sure if they can do CVS with so many babies though...they need to get a few cells from each placenta with out contaminating them with the other babies. I guess with the twins, they only need one sample.
NT tests for down, but CVS can give you results for everything, all the chromosomes and they do rapid tests for Trimsomy, 13, 18, down and the two X linked issues (turner X0 and kleinfelter XXY). I did my CVS on Friday and had those five results by Monday evening!
I have a friend who reduced from 4 to 2 and I can get you into contact with her if you would like so you can ask how she feels about it now. She now has two twin boys...
I am sorry you are in this situation! Let us know what happens and try to stay strong. Ah...this road is filled with surprises!
(((((HUGS)))))