And get it for purposes of this post, but be sure to differentiate between he is bad, and his "choices" are bad when dealing with him. Call the DR. help with all these experiences could only help.
Possibly if he saw his Dad hitting or abusing you he is acting out,as he has so many differant behavoral problems you could seek some councelling for him or a chat with the Doc.There is usually some anxiety when they play up like this, meanwhile how about you forget about Punishment stuff and focus on Positive things , had he something he particularly likes to do,can you distract him from his Tantrums,he could be Jealous of your Fiancee make sure you both pay him attention, as he is your Fiancee I assume you will marry how about asking him to do Guy stuff with your son , some Ball or reading and Games.