If you open MTA Server you can have more then 32 players there, if you have PC that can support that many people.
To map with your friends, if you can access your router to open 3 ports, you don't need Hamachi, just check this: https://wiki.multitheftauto.com/wiki/Server_Manual
If you are mapping in Map Editor, alone, you don't need to add anything in acl.xml. If you are hosting server for your friends to join, then yeah, you need. But if you are mapping on your own, from Map Editor, you already have all permissions you need without logging in, or setting up ACL.