I hope everyone won’t mind a general reply (my energy is limited due to cancer treatments).
Most of you understood my use cases (the development and deployment of secure websites), and you’ve offered interesting facts. I understand that LE will not act like a standard CA, in that it will not accept a CSR and SAN and return a certificate. I also understand that even if it did, it would not issue a certificate for localhost. I gather there is some way to use the local HOSTS file to obtain HTTPS access to websites under localhost (but I do not understand the instructions that were given).
As I indicated, I have no trouble creating a simple HTTPS website under WHM on a remote Linux system. This was the use case that receives my praise. So, my only remaining problem is being able to test HTTPS features locally, under localhost on a Windows computer. I still have no idea how this might be done, even if I could figure out how to use a separate .htaccess file that would run locally instead of the remote file (I guess I could write a command file to copy the right file to the right place just prior to FTPing the files to the remote site).
I was hoping for the same simplicity and reliability in applying LE to localhost as to a standard website, but so far I’m getting the message that this is impossible. I wish this use case had been included in the LE list of tasks, in spite of the fact that for me local development is done in the much disliked Windows environment. (If someone told me that development should be done on a live remote system, I would have to disagree. Similarly if someone told me that I should install Linux on my relatively tiny local computer just for the sake of website development.)