Ok if the list is really correct then we have two suspects. I will explain why others from the list cant be RJ.
First kirkland - if he was RJ lennon would recognise him and lorelie couldnt have known that he has shaken hands with jane

Smith cant be RJ because when he met Jane lorelei was in prison so she couldnt have known that he shook hands with Jane

Stiles isnt RJ because he wouldnt be described as a kid in 1988 because he was like 35-40 back then

Bertram isnt RJ because Smith told him it was his job to watch jane. RJ does not take orders so he isnt RJ

Partridge is dead ( if he isnt he is still a possible suspect )

you have haffner and sheriff thomas. I dont know if you guys remember this but Rosalind said that RJ likes to listen Bach so i would play Bach in front of haffner and sheriff thomas to see how they react.