A. - I suggest you check the mediawiki project's site on that issue with htaccess.
B. - I'm not sure you saw the part about XAMPP/LAMPP not being for production environments. The developers of the XAMPP suite intended it for use as a development platform (for programmers and designers). So, when they built it, they created an 'open' configuration. This was done deliberately, so developers wouldn't hit 'speed bumps' (problems to solve caused by hardening) when working. THUS - many potential 'ooopses' exist. But the use you propose is quite close to that. Its only when you 'open to the public' that it gets thorny.
C. - There is a basic fix available on the XAMPP Welcome Page under the topic 'Security'. It tells you how to run a XAMPP provided script that fixes the top issues.
D. - LAMPP is 'not' a true LAMP stack, so I suggest you read the bash script that powers lampp - its a file called 'opt/lampp/lampp'. A programmer's editor like geany that highlights syntax would make it more readable.
E. - If you are going to run it in an open as/is fashion, there's a page I wrote for the Windows version that discusses most of the issues, and they are basically the same for the Linux version: (includes a discussion about what is needed and what is not)http://bravo.newnetenterprises.com/word ... -security/
F. - Contrary to what some might tell you and the popular notions on the 'internet', you actually have to 'know some things' about your sever to use it properly and securely. Not doing so, leaves you open to the 'oopses'. There are whole pages/sites about hardening PHP and Linux. That's what Google is for, I use it all the time to learn new skills, and I have been a systems engineer for 25+ years -- still learning.
Disclaimer: These are all just 'my ideas', and don't represent the XAMPP project. (although I suspect Oswald would agree).