I also have a hard time figuring out the precise release order and dating of both Charlie Parker with Strings volumes. 1949? 1950? Vol. 2 in 1954? What songs were on what media, there were so many!

What are some surefire ways to get accurate dates online when even Discogs can be wrong?

So till bigger part of disco-graphical source for jazz are based on recording date chronological order (not release date). Best universal source based on date of release is still your mentioned Discogs, and in lesser part - rateyourmusic. We here on JMA use chronological order, based on date of RELEASE, and quite often it's not an easy work to find out when really original (first pressing) of one or another album has been released.  Bigger part of our added discographies is more or less placed in order now but job is continues and it will obviously will take still some time to finalize it.

RE. Charlie Parker albums from 49-50

It took some time for me to find out true order of Parker releases coming from that period but I hope what you can see now here is more or less representative:

http://www.jazzmusicarchives.com/artist/charlie-parker" rel="nofollow - http://www.jazzmusicarchives.com/artist/charlie-parker

As with some others known jazz musicians from that time, there is a lot of mess with their albums discogs coming from early 50s. The reason is changes in vinyl production technology at that time - early vinyl LPs,released during '49-'53 had less space for music, starting from 54 same physical size LPs (10'') can contain more music,so lot of albums, released during late 40s-early 50s on "smaller" space LPs during 1954-1955 have been reissued as "larger" space LPs. There were no rules how to combine previously released material completing new "larger" LPs, so one can find same title and same cover art "new" albums with material, coming from one "smaller" earlier LP plus part of other same artist "smaller" album of the same period, or combining one "smaller" album plus some EPs material, etc,etc. Some re-issues got original albums titles, others got totally new titles (containing exclusively already previously released material), etc,etc.

Our Parker section is good example illustrating that period situation. All first pressings are added under "Studio Albums", and all re-issues are added under "Compilations and Re-issues", many of re-issues contain comments about their content.

Just curious, what did you use to get the dates for Charlie Parker's stuff? I had been considering tracking down Bregman/Bukowski/Saks since Komara's is incomplete. I also saw something called "Bird Lore: A Revised Charlie Parker Discography." Ultimately, I guess the info comes from Billboard or internal letters?

it's a time consuming process, but using all initial info for each album, one can finally find out where and when each recording has been released for the first time, and where from content of one or another later re-issue comes from. 

good addition source of information (for parallel filtering) is jazzdisco.org

Thoughts on this one, or the Sarah Vaughan and Clifford Brown one mentioned in the opening post?

Here I would agree with you, most probably the year of release is 1961,not 1960 as stated on Discogs. First of all, the date of recording is November 13 and for early 60s I can't think about technological possibilities to release just recorded material on mass production vinyl in one and half month or faster.  Mobley's album catalog number is Blue Note BLP 4058, and previous Blue Note release (BLP 4057), released by Stanley Turrentine,according to same Discogs (and other sources) has been released in 1961. So, there are at least two reasons why the year of release is 1961, and I just corrected the data in our data base.

RE. Sarah Vaughan EmArcy MG-36004

Since it was recorded at December 1954,I can't imagine it was released still same year - so 1955 most probably.