I got so many answers. One "expert" even sent me a link to 2018 1040 instructions.
So no, I never got an answer via turbo tax. I suspect the answer is that turbo tax doesn't support this situation and no one wanted to say.
Here is what I ended up doing:
E-signed the federal form with my mom's name. Created a PIN for her. Entered her driver's license info. E-filed it via turbo tax.
Prepared the 2848 and 8453 on actual paper. Attached the POA and mailed it in.
For the state, I printed the filled out state taxes, signed it with a pen "my name, POA for my mom's name." Then I attached 2848 with the POA, included the check for the amount owed and mailed it via the post office.
The federal return was accepted within the hour. I'm thinking that when the check is cleared to the state, that will be my notification that it was also accepted.
If you learn anything else, I would appreciate if you would drop me a line.
