11 Why did Detective Sergeant Leane take 51 days to release news of finding the Tamam Shud slip?
On April 19th, 1949 Professor Cleland informed DS Leane that he had found the Tamam Shud slip in the fob pocket of the trousers worn by the deceased.
Then .. three weeks later
On May 3rd, an oblique mention of the slip was made in an Adelaide Advertiser news article . ” “New clues may identify Somerton Body. A small piece of paper printed in Turkish which was found in the dead man’s pocket has led police to assume he (the deceased) was able to speak that language.”
There was no mention in the article of the words Tamam Shud.
(1) Then .. on June 9th, 51 days after DS Leane learnt of Cleland’s discovery and a mere week before the inquest commenced, the Adelaide Advertiser was first to report the finding of a Tamam Shud slip on the body.
“Cryptic note found on body.”
(2) This was followed by another Advertiser article mentioning the Tamam Shud slip on June 10th. “Tamam Shud.”
June 17th. The Inquest commences.
Evidence is heard from Detective Brown and Professor Cleland mentioning the finding and translation of the Tamam Shud slip.
June 21st. The Inquest is adjourned.
(3) June 22nd. The Advertiser carries news of the discovery of the Tamam Shud slip in the deceased’s pocket.
(4) 25th June. The Smith’s Weekly (Sydney) carries news of a cryptic note containing the words Tamam Shud found in the deceased’s clothing. “Body on beach still baffles SA police.”
(5) 10th July. The Truth (Sydney) “Who is the mystery man? Puzzle of beach find.”
(6) 20th July. The Melbourne Age. “Torn Page.”
(7) 21st July. The Sydney Daily Telegraph. “Clue at long odds.”
(8) 22nd July. The Melbourne Argus carries an article “Torn Book May Be Clue To Somerton Body Mystery.”
(9) 22nd July. The Adelaide News carries an article “Remote book clue in mystery death.”
(10) 23rd July. Border Watch (Mt Gambier) “Search for a book with a torn page.”
(11) 23rd July. The Adelaide Advertiser “Detective – Sergeant R. L. Leane has been trying for several months to trace a copy of the “Rubaiyat of Omar Khayyam” from which the dead man is believed to have cut a piece of paper bearing the words “Taman Shud” (meaning “The End”) and placed it in the pocket of his trousers.”
Then, finally ..
23rd July. The Melbourne Herald “Detectives bring off a million to one chance. Rubaiyat clue may solve mystery death.”
23rd July. The Melbourne Herald. “Rubaiyat clue may solve mystery death. A motorist last night bought them a copy of the Rubaiyat of Omar Khayyam from which the last two words had been torn.”
Given the absence of proper police procedure in regard to the finding of a vital clue, it would appear someone wanted most the newspaper coverage concerning the finding of the Tamam Shud slip to take place after the inquest.
The Somerton Man 
It’d be interesting to know from Mr. Feltus (if you haven’t asked already?) whether the references to Leane in the first half of your list above are because the actions were verifiably performed by Leane individually, or whether he (Mr. Feltus) has used ‘Leane’ where an action may be unattributable to a specific individual because Leane was the head of the investigative team.
That is to say: are we dealing with accuracy, or precision?
Feltus was in a position to speak with all the police involved. Remember too that quite a number of people came forward thinking that they knew who the unknown man was, which meant there would have been a constant procession to the morgue. That would have kept a few of the investigative team busy. Not surprising that Leane would have delegated that particular job.