Ok, I gave up and moved to port 80, though i think what @Boultge suggest (the link) would have probably done it, but I read it too late.
Here are the files tho that are letting me run XAMPP WordPress MU sub-domain Multisite on localhost as wp.dev with 20 additional WordPress individual sites. I shortened it because i have 8 sites per line and both my wpmu and regular wordpress sites all look the same, i just have to be careful not to pick a name for a new multisite domain that i am already using for the regular wordpress
Here is the c:/windows/system32/drivers/etc/hosts
127.0.0.1 localhost
127.0.0.1 wp.dev
127.0.0.1 somename.wp.dev someothername.wp.dev wpmu1.wp.dev wpmu2.wp.dev wpmu3.wp.dev
In httpd.conf file located in xampp/apache/conf I have (all else left as is):
Listen 80 # line 47
ServerName localhost:80 # line
184
In httpd-vhosts.conf in xampp/apache/conf/extra:
DocumentRoot “D:/xampp/htdocs” ServerName localhost
DocumentRoot “D:/xampp/htdocs/regular-wordpress-1/wordpress” ServerName
somename.wp.dev
“D:/xampp/htdocs/regular-wordpress-1/wordpress”> Options Indexes
FollowSymLinks ExecCGI Includes Order allow,deny Allow from all
DocumentRoot “D:/xampp/htdocs/regular-wordpress-2/wordpress”
ServerName someothername.wp.dev
Options Indexes FollowSymLinks ExecCGI Includes
Order allow,deny
Allow from all
The rest of them above are all the same, each one a completely independent wordpress install.
At the very end of httpd-vhosts.conf comes multisite domains below:
DocumentRoot “D:/xampp/htdocs/wpmu-home/wordpress”
ServerAlias wpmu1.wp.dev
ServerAlias wpmu2.wp.dev
ServerAlias wpmu3.wp.dev
ServerName wp.dev
Options Indexes FollowSymLinks ExecCGI Includes
Order allow,deny
Allow from all
No other directive is activated besides what’s here in the httpd-vhosts. With this sub domain wordpress multisite on xampp works fine though on port 80.