Suspects through the years?

I've read many threads that say that Tracey has implicated other people in the JBR murder, also - what were their names and were they investigated and cleared?

Besides the obvious Ramsey's, who else has been considered a suspect, investigated and cleared?

I've heard mention of Helgoth. I've also heard the name Oliva. Can anyone give me a rundown on why they were suspects, or what came of the investigation?

I know there would've been a lot of people to look at from the party (Whites??) and I've heard mention of "Santa", too - but am not familiar enough with all the other players to know who is who. I'd assume that family friends, coworkers, JBR's teachers and even pageant people would've been at least interviewed, is that correct?

TIA to all of you who know so much more detail about this case.