Buddypress is a feature of wordpress. I am not sure that it is possible via any plugin or by a simple migration process.

You can do a database mapping but that would be a hell of a task. Alternatively you can do an export of all the objects from elgg and check how those object can be imported in wordpress via any custom script. There might be other solution as well but any solution you choose will required a hard core technical knowledge of both Elgg and Wordpress. Even if you find someone with such expertise, do ensure that all the plugin that you were using in Elgg has an equivalent plugin in Wordpress.

For now, all I can say is all the best..!!

If the folder exists it will not come under elgg. This is the default feature you don't need to do anything extra.

Ensure that the "one directory" has an index.php file.

Thanks, Rohit. That's what I needed to know. My mistake was that I had put a test "index.html" file in my new folder, and the standard .htaccess requires only "index.php" as a "default handler".

I thought this must be more simple than I was making it! ;-)

@Rohit Gupta I want to change the routing structure .

Elgg 1.8 is very old and there is no documents available for the same.

I don't think trying to rewrite the whole routing structure makes any sense just for the chance to improve SEO rating. First of all, you would need coding experience to do it. It's not a task anyone could explain to you easily and step by step. It would be a task that would take some time to explain and then to implement (by you - again: without coding experience you would probably fail).

Then one problem with improving the ranking but using Elgg 1.8 is that for example Google takes into account how mobile friendly a site is. And an Elgg site with Elgg 1.8 is not. Newer versions of Elgg come with the responsive Aalborg theme that is much more mobile friendly (responsive means that it would adjust to different screen resolutions). So, really think about upgrading your site to a newer Elgg version. It will take some time to prepare, maybe also to learn how to do it but at some point you should do it.

Most likely the only really promising way to improve your ranking is to have relevant, unique content people are interested in and spend time with reading and maybe also share with on other sites (links to your site etc.). If you try it the other way round and just have a vast collection of stuff reposted from elsewhere it might not help. There's probably no magic involved here but difficult to achieve nonetheless. I don't think there's the perfect plan available to automatically get a top ranking or every site that tries to monetaries would follow it.