WordPress 4.2 introduced new order by clauses for meta_query.
https://make.wordpress.org/core/2015/03/30/query-improvements-in-wp-4-2-orderby-and-meta_query/
Which would probably let you do what you looking for.
By the way, very good solution for altering ‘meta_key =’ to ‘meta_key LIKE’. I know I”l be using that in the future.
