Here’s something that might help some folks:
I did the following things to get LP working and with a clean Plugins list:
1) Put the LivePress folder in the /wp-content folder (same level as the plugins folder)
2) Put LivePress.php in the /wp-content/plugins folder.
3) Make sure your /LivePress/lpsynch.config.php file is editted properly (the file is fairly clear on how to do it. Make sure you insert your LJ name on both $journal lines (password and allowlist).
4) Update the path for all the files in the /plugins/LivePress.php file to reflect the correct/full path to the LivePress folder (this depends on your overall WP install).
5) This was the key for me: If the class-IXR.php file already exists in your wp-includes folder, OVERWRITE IT with the one that came with the LivePress zip file! The intro.txt file specifically says not to do this, but my install only started working once I did. cococo references this, I’m repeating it’s usefulness.
Thanks also to jennmiller for her help.