Hi! Your post caught my eye because I have both Macht's and Applegate's that I research. It doesn't look like you and I are researching the same lines but thought I would include some information that I looked up for you.
Pearl and Ellen are NOT in the Social Security Death Index. Louetta does not have a SSN according to the CA Death Index. Hubert was listed in the SSDI database. His entry was as follows:
HUBERT APPLEGATE19 Sep 1899 Dec 1978 92367 (California) (none specified) 549-66-0204 California
Hope this helps! It looks like your Ellen might be a cousin NOT a sibling of Pearl and Hubert. You can apply directly to the specific counties for copies of their death certificates if you so desire. Do NOT request copies from the State of CA in Sacramento, they are backlogged 6-12 months minimum.