Both the approaches works fine, but I prefer the first approach because, if you import them on latest designer you can check for any compatibility errors, you can correct them and then publish them to new servers, so that you can have a code base of latest version. So any new enhancements after upgarde, you can use this as code repositoty.
But if you follow the 2nd approach, your migration scripts will migrate your MWS file system from source to destination and then you can init and start your new MWS server. I have already done this and tested, no major issues except some exception in MWS logs because of node name copied from source, once you chnage this to new and restart then your MWS server perfectly works. but here you may not be having code base of latest version.
I have a question… while doing the replica of existing DB schema, have the DB team copied along with the tables or they just created the schema then you run the DB Configurator?
If you want to migrate MWS, then you need to copy whole DB schema having tables and contents inside them, if you are moving (doing replica of) your DB.
If you use fresh DB schema, then its equivalent to creating new MWS.