I was under the impression–and I can’t recall where I got that impression–that “felony murder”, as you describe it, is first degree murder.
I think First Degree has to be preplanned, intentional and calculated. It can’t be as a result of an argument or a fight you thought they had a gun but they really didn’t. First degree is reserved for when you definitely wanted them dead on purpose and you planned ahead for it.
Premeditation can happen in one second. “Preplanning” implies that one has to make a plot an appreciable amount in advance, like slipping arsenic into someone’s tea.
Please. You cannot legally consent to an illegal act. Plain and simple.
Google " Armin Meiwes" for more information. But only if you have a strong stomach.
Or just click on a thread linked in post 12. 
I probably shouldn’t have read that thread while finishing a bologna sandwich.
As for the OP, I don’t know a lot about different categories of homicide, but what you describe was definitely a serious felony.
Could’ve been worse. You could’ve been eating a knackwurst.