hide .php extension & force trailing slash - regex

Question

I've been trying to delete the .php extension and force trailing slashes in the end of the URLs.
I've found an answer to do it exactly what I need at (.htaccess trouble with hiding file extension and forcing trailing slash) but it does not work, I believe it's due to how I am forcing my website to change the document root.
As I do not have access to Virtual Hosts I must change my document root using htaccess, and I have accomplished it by applying the following code..
RewriteCond %{HTTP_HOST} ^site.co$ [NC]
RewriteRule ^(.*)$ http://www.site.co/$1 [R=301,L]
RewriteCond %{REQUEST_URI} !webroot/
RewriteRule (.*) /webroot/$1 [L]
The only working solution that I've been able to apply to hide the .php extension is with the code below.
removing .php extension(only working solution)
RewriteCond %{THE_REQUEST} ^\w+\ /(.*)\.php(\?.*)?\ HTTP/
RewriteRule ^ http://%{HTTP_HOST}/%1 [R=301]
RewriteCond %{REQUEST_FILENAME}.php -f
RewriteRule .* $0.php
This code is in the thread that I have linked above, but it does not work on my website as I believe it's due to the document root.
RewriteEngine on
# Forces a trailing slash to be added
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule ^(.+?[^/])$ /$1/ [R=301,L]
# .php ext hiding
RewriteCond %{REQUEST_FILENAME} !-d
RewriteCond %{DOCUMENT_ROOT}/$1.php -f
RewriteRule ^(.+?)/?$ /$1.php [L]

Answer 1

Try these modified rules with different ordering:
RewriteEngine on
# add www before hostname
RewriteCond %{HTTP_HOST} ^site\.co$ [NC]
RewriteRule ^ http://www.%{HTTP_HOST}%{REQUEST_URI} [R=302,L,NE]
# if on article page, get slugs and make into friendly url
RewriteCond %{THE_REQUEST} \s/article\.php\?article_uid=([^&]+)&article_title=([^&\ ]+)
RewriteRule ^ /article/%1/%2/? [L,R=302,NE]
# if page with .php is requested then remove the extension
RewriteCond %{THE_REQUEST} \s/+(.+?)\.php[\s?] [NC]
RewriteRule ^ /%1/ [R=302,L,NE]
# Force a trailing slash to be added
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteCond %{THE_REQUEST} \s/+([^.]+?[^/.])[\s?] [NC]
RewriteRule ^ /%1/ [R=302,L]
# allow page direction to change the slugs into friendly seo URL
RewriteCond %{REQUEST_FILENAME} !-d
RewriteCond %{REQUEST_FILENAME} !-f
RewriteRule (?:^|/)article/([^/]+)/([^/]+)/?$ /webroot/article.php?article_uid=$1&article_title=$2 [L,QSA,NC]
# silently rewrite to webroot
RewriteCond %{REQUEST_URI} !/webroot/ [NC]
RewriteRule ^ /webroot%{REQUEST_URI} [L]
# .php ext hiding
RewriteCond %{REQUEST_FILENAME} !-d
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME}.php -f
RewriteRule ^(.+?)/?$ $1.php [L]