@murz I had a similar situation, i needed to inherit the props from my original component in the one I was overriding. SDC requires you to define the props key in the ComponentValidator Class.
Here was my situation;
Theme A - Button Component
Theme B (child theme of A) - Button Component, replaces: theme_a:button
I didn't want to have to redefine all the props again in Theme B's button.component.yml file so I created a small helper module that when the replaces key exists and props are omitted, it loads them from the parent. You can also add new props, or if one already exists, yours will take precedence, allowing for "mixed" props (inheirt base ones from the parent, and override in your own component).
This made it possible to have a really slim component yaml file and my 1 twig template, and I automatically got all the prop/schema changes from the parent.
I feel like this should be part of core... maybe under a new yaml entry like props: inherit or something. Otherwise I can add a new project, but i wonder how many others would benefit from this functionality.
Marking as RTBC, will merge into dev this week.