What evidence is needed to prove birth and death dates?

I am trying to add birth and death dates for a dancer, Meurisse Duree https://www.imdb.com/name/nm13159631/?ref_=fn_al_nm_1 (Contributor Submission #211125-185002-132000) and it has been rejected. IMDb has accepted that his birth name was Meurisse Owen Helm.  In respect to the birth/death information, have included the following:

1.  California Death Index (pdf page from Ancestry.com) for Meurisse O Duree giving birth date and place, death date and place.

2. Page from the 1940 US Census, East Denver, CO (pdf from Ancestry.com) showing Meurisse Helm, age 6 (supports 1933 birth year given on Death Index) and birth place consistent with CA Death Index.

3. Page from Find-a-Grave for Meurisse Owen Helm (pdf of webpage) for his burial in Denver, giving his birth date and place, death date and place, a short bio stating that he was a dancer and graduated from E. Denver High school, gives his parents names consistent with 1940 Census, and shows a photo of his tombstone with his name given as Meurisse Du Ree Helm and birth and death dates agreeing with the CA Death Index.

4. Passenger manifest from a 1957 ocean liner (pdf from Ancestry.com) with passenger Meurisse /known as Duree/ Helm giving same birth date as Death Index and Grave information. His profession is recorded as "dancer"

Some of my other data submitted to prove other facts (e.g. his birth name) was not included in these two submissions since his variable name has been accepted and this data does not relate specifically to birth and death facts, but I am wondering if I should have repeated it here.

I have submitted this type of info for other persons and had it accepted, and am wondering why this is insufficient, as the CA Death Index is an official document, the passenger manifest is an official document, the gravestone gives consistent information, and the census (likewise an official document) also supports the same information.

Are the pdfs inaccessible? Are the sources considered unofficial/unpublished? I am not sure what the problem is.

Thanks for your assistance,

Glenn P.