"Debunking" suspects & theories
The organized crime hits/slave ring theory - I understand why some might entertain this thought, but I think if you look at the specific stats of the victims: White, young, small statured, drug addicted, mostly not from the immediate area, used craigslist, etc. you would agree that someone is targeting a specific type of victim. If the victims were wacked/killed for business reasons the victims would have a diverse range of age, race, size etc. If it was motivated by business, it would be more or less a random sampling from the population of sex workers, and that random sample would not be all white etc.
MP as suspect - It has been documented in the media that MP returned to oak beach to look for SG after he found out that she never made it home, and then went to the SCPD presinct to file a missing persons report, I must assume the police checked the integrity of that claim because interaction with the police is documented. I don't believe he could be responsible for what happened to her since he returned to Oak Beach and went to the police to report her missing.
Theory that Manorville killer is different from the killer of the original Gilgo 4 - I still have a hard time believing the DA or anyone is this stupid, I think the claim is a ruse. I see nothing strange about a SK changing the way he operates over a decade. Also, being from LI, I think the probability of 2 SK's using ocean parkway is much more UNLIKELY than people think it is. The truth is there are Hundreds (I would even say an uncountable amount) of woodsy locations on LI suitable for disposal. It is perfectly logical to say the probability of 1 SK changing details of his kill over a decade is MUCH MUCH higher than the probability of 2 prostitute killing SK's dumping within hundreds of yards of each other on an Island that is 1,401 square miles.
The Mural Artist
To a hammer everything looks like a nail, if you sleuth every detail about anyone you will think you see "creepiness" or a potential subject. There is no reason to be concerned about a painter who likes to paint girls, etc. I agree he is the victim of 1 (emphasis on 1) unfortunate coincidence: skulls in painting.