pabloklaver
Hi
Both are different templates if you have Articles with JA Content types in JA Teline V the same will not work like Topic type is not support in the JA Focus, all the articles will be appeared as Normal Joomla article and use the JA Focus template layout style.
JA Focus only has article video and Gallery content types.
To best way to test, you can take backup of site and install it on localhost or staging site, Install JA Focus template on it, set it as default template and try some changes as in JA Focus documentation.
As JA Focus does not have Special page blank type menu and also it loads all modules via modules position with different style and layouts.
Regards