Felony murder is still a capital crime, in Georgia. So they get the fullest possible punishment, but without the little hiccup of having to prove this was premeditated.
Ugh. I know that intent was going to be hard to prove here all along, but it feels like a cop out. They have not added any additional charges beyond the original burglary charges; I am assuming that the felony murder is for a murder committed in the commission of a burglary, not a rape, which would also be a harder intent to prove.
Proving an intent to commit burglary for McD will not be hard, given previous events.
I wonder if the DA is going for the "thieving almost-lawyer caught in the act" scenario. Stephen was using his key to go through Lauren's apartment to try and steal more trophies/condoms, when Lauren got home and interrupted him. Realizing that his legal career is DOA with a burglary charge, he kills her to keep her from speaking.
I don't believe it for a second, but that would be a pretty reasonable scenario to try and prove.