reposted Changing remote repository for a git submodule – Stack Overflow

These commands will do the work on command prompt without altering any files on local repository

git config --file=.gitmodules submodule.Submod.url
git config --file=.gitmodules submodule.Submod.branch Development
git submodule sync
git submodule update --init --recursive --remote
Please look at the blog for screenshots: Changing GIT submodules URL/Branch to other URL/branch of same repository

Why Categorize when you have Post Kinds and Tags – Disabling categories in WordPress

Consider putting all your changes in a child theme. Look at my child theme as an example.

add to functions.php in your theme:

function dougbeal_unregister_categories() {
    register_taxonomy( 'category', array() );
add_action( 'init', 'dougbeal_unregister_categories' );
unregister_widget( 'WP_Widget_Categories' );