Dynamically Filtering Posts by Data Points – Any Pointers?

In my opinion the best way to achieve what you want is to use custom fields and meta query linked with a WP Query and Ajax. You can find the documentation here : https://codex.wordpress.org/Class_Reference/WP_Query#Custom_Field_Parameters

An example of a WP_Query with meta_query :

new WP_Query(array(
    'post_type' => array('post_links', 'page'),
    'meta_query' => array(
        'relation' => 'AND',
        'cost' => array(
            'key' => 'cost',
            'value' => '500',
            'compare' => '<=',
        ),
        'country' => array(
            'key' => 'country',
            'compare' => 'France',
        ), 
        'city' => array(
            'key' => 'city',
            'compare' => 'EXISTS',
        ), 
    ),
    'orderby' => array( 
        'cost' => 'ASC',
        'city' => 'ASC',
    ),
));

Another way to do it as you way is another table to stock data, depends of your needs and the quantity of data you’ve to stock.