Woocommerce getting top level category parent and make all sub categories have the same template and menu

WP native function get_queried_object() can help you to get an ID of a currently displayed term.

WooCommerce then includes this handy function: woocommerce_get_term_top_most_parent() (originated here on WPSE btw,) that will get it’s top-level parent term.

I haven’t tested the following code but it should provide a good starting point:

if ( 'wedgwood' == woocommerce_get_term_top_most_parent( get_queried_object()->term_id )->slug ) {
    // your code-fu here ...
}

Regarding the template redirect part of your question – take a look at:
Creating a default Custom Post Template that a Theme can override

Reference: