Can you please check if the following sentences are possible? I did some of the corrections myself.

1.He hoped to find Kurtz dead on his arrival at the inner station. He hoped that Marlow would find Kurtz dead by the time he got there.
2.The manager wanted to take Kurtz’s place. ( can you say: to take over Kurtz’s place as manager of the inner station).The Expedition consisted of little groups of men who went to Africa to search for ivory (can you also say: “in search of ivory, to look for ivory?)
3.The message was for us. It read: “Wood for you. Hurry up. Approach cautiously.” Marlow found a message (for them) urging them to hurry up because there was wood for them. It also warned them to approach cautiously (Is there a better was to report this message that Marlow found in the broken-down hut??). He found a message which read (and NOT which said?): “Wood for you……”
4.In the hut Marlow found a book about seamanship full of calculations and tables, whose (??) margin had notes written in a kind of code. The code remained a mystery (indecipherable or incomprehensible?) to Marlow.
5.Marlow told the other sailors who Kurtz was, his origin and the book he had written. (Correction: He told them who Kurtz was. In particular, he told them about Kurtz’s family and about the report he was asked to write about Africa).

3 - Change the colon to a comma. Keep the first two sentences; delete the rest.

4 - "... tables, which had margin notes written in a kind of code."

1 - 4 -- Delete everything in parentheses.

5 - The correction looks good.