MaryLandT, thanks for looking at my issues.
First, I had attached a marked-up Income Statement (created from within Sample Company) to help anyone follow along but it may not have gone as I cannot open it from the post. Here it is again.
On Issue 1, I am aware how to link a sub-account to its parent account. But the issue that I describe is several levels above that (i) taking into account my accounting objectives, and (ii) the apparent QB Desktop limitation of having only one set of "Other Income" followed by one set of Other Expense" accounts below Net Ordinary Income . Could I ask you to please re-read Issue 1 (hopefully, with the detailed attachment) and see if you have an answer and, if not, I understand.
On Issue 2, I researched it more within Sample Company and you are right. "Car/Truck Expense" is an example of an Income Statement account that has sub-accounts attached to it and is listed as the last entry in the list with "Car/Truck Expense-Other". That's fine because, in a regular report that we would normally set to only print accounts with activity, those header-accounts will not appear. And if an amount gets posted there by mistake, it will print and can be reversed or journaled out.