Hi Pablo. I'm actually a current student in the program, graduating in a few weeks. Not sure how moretodo is getting this information as he is not, to my knowledge, a current student. I came into the program without any experience, and was able to secure an internship at Goldman Sachs, and recently took a full-time offer in automated trading at a different bank.
The lack of experience in this program can actually be a huge advantage as your projects become your experience in interviews. In my case, I did projects that I was extremely passionate about and hence got interviews for positions I was passionate about. The program is in my opinion the best in the world when it comes to selling you to employers, but you do need to make sure you have interesting selling points. However, I don't think you would get an offer if they didn't think they could sell you easily.
On the topic of admit conditions, all I can tell you is I completed all of mine. One of mine was the GRE, and I found it helpful when it came to interview tests, which can sometimes follow the GRE math format. The preprogram classes get you prepared for the material in the program, and they're actually taught by professors you'll see in the MFE. To my knowledge everyone took the preprogram courses that were assigned. I wasn't assigned the CFA so I can't comment on that, but I know quite a few students were and completed it.