If you are using SQL compact (part of the default installation of Lansweeper), you don't need any Microsoft SQL server components on your Lansweeper server. SQL compact is fully integrated into the application.
Please note that if you are scanning more than 1000 assets we recommend installing your database onto SQL Server Express or higher edition as SQL Compact can't handle the number of database requests involved in that. In this case, you only need a standard SQL server installation. Additional features are not required for Lansweeper itself.