babysteps, I am LD as well. It has never interfered with my driving...you just cant hear having nothing to do with your vision or reactions. yeah, we may get hit by some idiotic driver but that's life, we wont hear it coming but will sure feel it after the facts.
Living alone... no reason to be scared shitless. Request a hearing service dog and be specific what you want it to hear for you as it will be trained very specifically, you will also be schooled in the 2 weeks before bringing your SA home, they will show you how to add commands ( usually Target Training )
as far as doorbell, you can get wireless flashing doorbells from VR (Vocational Rehab) in your local area as well as lots of other useful stuff (alarm clocks/phones/bed shaker..ect) I myself am slow with learning ASL, relying more on lip reading as I did when I was a kid, haven't done it in years since shying away from it during my highschool years as I went to a pretty bad school as everyone took it as aggressive when watching them. I am picking up more on ASL as far as "reading" but my brain/hand coordination isn't so quick, and besides with strong laboring so many years my fingers don't want to cooperate as well either.