Peripheral to the substance provided by 1nickt and tobyink, I will leave here what I learned trying to find alternatives for the shelling-out from 1nickt's excellent demo.

I have tested 2 modules for SQL'ing from a file: DBIx::RunSQL (for both files and strings and quite recent too!) and DBIx::MultiStatementDo for SQL strings. And they work great. We are talking about multiple SQL statements spanning over many lines, etc. So using either of those modules will avoid shelling out for mysql. Added bonus & most importantly both are DB-vendor agnostic: just supply a DSN.

Also, I have tested replacing shelling out dbicdump with DBIx::Class::Schema::Loader's make_schema_at() and that works fine too.

thank you again 1nickt and tobyink, bw bliako