Will it work if I were to run gadmin-proftpd for a GUI? or will this mess up lampp?
You can probably use it as it was meant for standalone ProFTPd, you will likely have to configure it slightly differently as your distribution will not be aware that proFTPd is installed. I think what I am saying there is you will need to 'feed it the path'.
You also have the choice to not run ProFTPd at all and install it 'standalone' and configure it so at least one user's home path is '/opt/lampp/'.
If you haven't, be absolutely sure to read this page
http://www.apachefriends.org/en/xampp-linux.htmland especially note this:
startftp Starts the ProFTPD server. Via FTP you can upload files for your web server (user "nobody", password "lampp"). This command activates the ProFTPD permanently, e.g. if you restarts XAMPP in the future FTP will stay activated.
....
stopftp Stops the ProFTPD server. This command deactivates the ProFTPD permanently, e.g. if you restarts XAMPP in the future FTP will stay deactivated.
That will 'fix the issue' if you want to install ProFTPd standalone.
Two other things:
A. LAMPP is NOT a LAMP stack, its a bash script that does everything via 'command line calls' - you should look at/in the file '/opt/lampp/lampp'. Read that as - don't expect it to work like many examples found elsewhere would lead you to believe.
B. Don't tinker with the ownership of /opt/lampp, because some things may stop working. you can certainly experiment inside /opt/lampp/htdocs, as you can always take it back to nobody:root.
The next is a COMPLETELY personal comment, and should not be taken wrong, as I don't know your background or what you intend to use XAMPP/LAMPP for.
In the linux world, GUI's are a luxury, and one not afforded by most real 'servers' (as they are usually remote, even if they are yours). As ugly as it may be, I recommend everyone learn the command line interface (aka 'term' and/or shell) and an editor that works from the command line - like vi or nano. Some things are just not 'do-able' without getting 'down-and-ugly'.
This is spoken as someone who earns his living 'doing this stuff'.
Good Luck with LAMPP