1. Move the WP code below the Redirects
2. Uncomment the index.html Redirect
3. Add (at the top) DirectoryIndex index.php (which will redirect / to index.php internally).
... for the reasons in the thread post above.
# My general layout
# Core directives, i.e., Options, DirectoryIndex, ErrorDocument (WP takes care of this)
# Core redirections (i.e., your Redirect statements)
# mod_rewrite statements
# WP mod_rewrite should be "corrected" by removal of
# - <IfModule> wrapper
# - RewriteBase directive