Remove CSS Attribute by Overriding CSS in Child Theme

I’m assuming that this is happening because the style sheet will only
override the attributes that exist in the parent theme and child
theme; thus, leaving attributes that are NOT in the child theme, in
the parent theme.

That’s not how it works. There’s nothing special about WordPress parent theme and child theme stylesheets. They’re just standard CSS style sheets, and they follow the same rules as any two stylesheets loaded on any other web page.

If you want to “remove” a style from one stylesheet in subsequent stylesheet, you need to provide a new value for it. If you have a position: relative; property, and you want to reset it to its default value you need to use initial:

.mvp-blog-story-img img {
    margin: 0 auto;
    width: 100%;
    min-width: 0px;
    position: initial;
}

Note that initial doesn’t work in Internet Explorer, so if IE support is required, you will need to find out what the default value is and set it to that. For position, that’s static:

.mvp-blog-story-img img {
    margin: 0 auto;
    width: 100%;
    min-width: 0px;
    position: initial;
}

Note that if the element’s position is static then left and right won’t do anything, so you don’t need to reset those.

To find the default values for properties, the MDN web docs CSS reference is a good resource.