Greetings, Yes, ListMail can be installed along-side other scripts in the same MySQL database. ListMail takes care not to remove tables created by other scripts. There are no blind "drop all tables in database" commands which might be found in some scripts.
The only thing you'll want to watch out for is that aMember also does not touch any tables that it has not created. I'd venture a guess that they have taken care to avoid affecting other tables in the same database, too.
Regards