I'm not sure if it makes a difference if you're using a VM, especially if you're just using it for testing at this point

The only reason I want to use windows is because of the extras it brings

I could run multiple elgg sites

I could incorperate Active Directory and othe features into Elgg

I can run other OS in the background like FaceBook does for Elgg

I can keep Mysql on a seperate drive as whell as my user data and photo and game data

If you can please tell me why this would be a bad idea?

Also I can run Adobe and Visual Studio on windows

If you'd like virtualization, just configure vagrant box for your needs, something like: https://github.com/Srokap/elgg_vagrant (debian75-x64, but still WIP so you'd need to adjust it to your needs). Should be easier to maintain your environment. Something to look at as well: https://puphpet.com/

I still use http://www.wampserver.com/en/ on my Windows 8.1, especially useful when having 3 versions of Apache and 4 of PHP and you want to switch easily between them. Still some manual adjusting is needed for it to switch smoothly.

Elgg is written in PHP, plugins are PHP only.  I'm not sure what you mean by 'can handle other languages' but the answer is no.

That's a badly asked question. Elgg is a PHP framework, so the answer to your question as for almost every PHP framework is no.

You ask about languages, but link to article speaking about something different.

• Elgg integrates with memcached, check settings.php
• Last time I've checked, Elgg wasn't running smoothly on hiphop, though there were several changes since that time, so perhaps it's worth revisiting: https://github.com/Elgg/Elgg/issues/6248 I don't recommend it for a production use at the moment.
• You can implement custom file storages in Elgg
• It's possible to combine Elgg with middleware solution to construct page from computed separately parts, ie. the system I was designing (if you dare to bare with my terrible accent: https://www.youtube.com/watch?v=RhISiQuc6OQ).
• Minds made cassandra fork of Elgg, though it's not open-source'd just yet AFAIK
• There's no Thrift support in Elgg, but nothing stops you from using it https://thrift.apache.org/tutorial/php, I wouldn't expect good ROI there and I can't vouch for a stability of this extension
• Elgg integrates well with Varnish if you know what to cache and what not in your Varnish configuration. If made correctly, you can gain a lot by using it.
• For profiling, I can recommend Xdebug, though that's not something to keep constantly enabled on production site.

That's regarding topics in the article. Please ask more precise questions in future.