In April 2017, when I was preparing to move (for the last time in my life; my next move will be in a hearse), I was looking for a way to enjoy a few billion pictures in the new home and in my retirement years. I would up buying a Samsung 65" smart TV for the living room; 48" smart TVs for the four bedrooms, dining room, garage, and covered patio; 36" smart TVs for the three bathrooms, kitchen, catio, and laundry room. I bought 64 GB flash drives for all of them, copied various files to them (fauna, flora, trains, cars, planes, aquariums, zoos, places), plugged them in, turned the TVs on, and they play 24 hours a day, 7 days a week. Pictures are set to rotate in chronological order with at 15 seconds per picture. Much better than watching television!

1. Yes, <auto> is a good starting point
2. No, the WB is determined by the camera, either via a AUTO-WB setting or something the photographer (you) set when capturing the image. There's nothing about the JPEG format that impacts the WB of the image that is different than any other image file format.
3. I use an older version of LR. I've seen comments that Adobe has improved the intelligence of <Auto> vs older versions. A subscription user would need to comment.

Regarding an edit workflow. Personally, I import all my RAW images into LR and the apply Develop Presets I have developed that accomplish:

a. Apply the lens profile for the lens version used.
b. Set the camera profile to Camera Standard.
c. Apply ISO-specific noise and sharpening values I've developed for my individual cameras.
d. Apply default values of Clarity, Luminance and Saturation I've developed for my individual cameras.
e. Trigger Auto WB and Auto Develop.

Before editing, I try to remember to add keywords and move all images to a collection in my library. This can be done later, but I've found it best to do this admin work up-front.

I then begin editing images individually, with the images sorted by capture time. Given I have a string of images, they’ll typically be from the same lighting situations. I edit the first to my desire, moving / correcting the individual sliders on the first image. LR's <auto> is what might be called a "disaster" relative to both the original and the final version. But, the ideas of what to correct are useful, many times giving ideas I would not have considered by myself.

When I finish editing the first image, I then use the ‘power’ of LR by syncing the settings from the first edit across the next similar images. Sometimes, they’re all good or they require individual, but minor, addition tweaks. Sometimes, I sync those additional edits back across all the images, other times the images remain unique. It does depend.

"Syncing" is done by selecting multiple images from the film role in Develop, or the Grid in Library via Sync Settings. You can uncheck all and then select just WB and Exposure, or whatever specific setting to sync. So whether you start from Auto or just the imported version, the power of LR is the syncing function across similar images where every image doesn't have to be edited from scratch.

As you edit, use the backslash "\" and flip back n forth from the original to the current status of your edits. Sometimes the history panel is useful as I have at least three points of reference: initial import, application of the preset triggering the auto develop and auto WB, and the current status of the editing.

Use utube videos or your books for examples and explanations for each slider. As <Auto> doesn’t touch Clarity, Vibrance and Saturation, my presets apply values for these sliders.

I first get the "basic" edits of the exposure and White Balance completed, then give a second pass for cropping, cloning or anything more complex. I also tweak noise and / or sharpen and sync these refinements across similar images, using the syncing function and updating the parameters being synced to just these settings.

I use the image compare tool throughout the process to identify and discard duplicate or inferior images, setting them to rejected and removing from the edit session. If I do my work from within a LR collection, I can periodically filter by rejected images and remove the rejects from the collection without impacting their status in the Library. At the end of the session, I delete all rejected images, both from the catalog and from disk.

Regarding my (a) to (e) preset actions, you can do these manually in-mass from the Library module as well. Use your Metadata filters to identify and isolate images by cameras and / or lens models. You'll then update one image with the lens profile and camera profile (Camera Standard or other) and sync those settings across all images from the same camera and lens.