I was able to setup a subdomain url for an existing blog.
http://gameshogun.ws/index.php/links/ or http://gameshogun.ws/links/ can now be accessed via http://links.gameshogun.ws/

It's all good.

Though, b2e itself, when generating links for the blog is including the index.php in the URI. The no index.php .htaccess code do not kicks in for this (the code shown below)

# If we have an .html file for the bare subject (no extra path, no query string), use it:
RewriteCond %{REQUEST_FILENAME}.html  -s
RewriteCond %{QUERY_STRING}  ^$
RewriteRule ^(links)/?$  $1.html

# If the subject/extrapath does not match an existing file, call b2evo!
RewriteCond %{REQUEST_FILENAME} !-s
RewriteRule ^(links)(/.*)?$  $1.php

So I also changed the other setting Explicit reference to a stub file, the way it should be to remove the index.php

It works, it's good, coz it still keeps all the old links active, example -
OLD URLs like these will still work:
http://domain.tld/index.php/blogname/$1
http://domain.tld/blogname/$1

NEW valid URLs:
http://blogname.domain.tld/index.php/blogname/$1
http://blogname.domain.tld/blogname/$1

Cool, with this setup, I am able to removed the dreaded index.php from b2e URL generation process. BUT, I'm still stuck with b2e generating the stubname as well.

All links generated now are always in this format: http://blogname.domain.tld/blogname/$1

Now I want b2e not to produce the 'blogname' since its already the subdomain. If I switch the setting back to Automatic Detection by index.php, b2e will instead produce index.php (as well as OLD URLs without the index.php will stop to work).

Anyone here who knows how to keep b2e to produce the proper URL?

----

For the second and last question, regarding .htaccess HTTP 301 Permanent Redirect.

How should I write the syntax to redirect these URLs:
http://domain.tld/index.php/blogname/$1 -> http://blogname.domain.tld/$1

http://domain.tld/blogname/$1 -> http://blogname.domain.tld/$1

My current code:

RewriteCond %{HTTP_HOST} ^([a-z0-9-]+\.)?gameshogun\.info$
RewriteRule (.*) http://gameshogun.ws/$1 [R=301]

RewriteCond %{HTTP_HOST} ^www\.gameshogun\.ws$
RewriteRule (.*) http://gameshogun.ws/$1 [R=301]

If I add either or all of these:

RewriteCond %{HTTP_HOST} ^www\.gameshogun\.ws/blogname$
RewriteRule (.*) http://blogname.gameshogun.ws/$1 [R=301]

RewriteCond %{HTTP_HOST} ^www\.gameshogun\.ws/index.php$
RewriteRule (.*) http://blogname.gameshogun.ws/$1 [R=301]

RewriteCond %{HTTP_HOST} ^www\.gameshogun\.ws/index.php/blogname$
RewriteRule (.*) http://blogname.gameshogun.ws/$1 [R=301]

It doesn't work. It is as if apache do not recognize redirection beyond the .tld part.

Thank you very much to all.