Changing OS X's Apache settings to replicate Ubuntu's Apache environment
You can always do a clean install, from source, of Apache HTTPD, with whatever settings appeal to you. If you want it to walk, talk, and quack like Ubuntu, choose pathnames, user-ids, and everything else to match as part of the 'configure' process. All you need to do to your stock Apple deployment is turn it off to avoid avoid port conflicts.

You could try to reconfigure the Apple default install to be more Ubuntu-ish, but you risk getting tripped up by some obscure decision made by Apple, up to and including source mods. So I suggest that your best best is to use the source, as its authors intend.