Hi John,
No, our plan is install maxdb>>Backup/Restore>>Upgrade to MSSQL Server 2008 SR2
It's fine,for this you need to follow SAP Heterogeneous System Copy methods located at https://websmp206.sap-ag.de/~sapidb/011000358700000877172012E/Copy_NW71X_bsd_syst_SWPM10.htm
So that means i have to add the freshly sandbox system into solman ??.
If the system is completely identical for which you've already generated stack.xml then opt the report to use copy stack configuration,otherwise yes you need to define sandbox in to Solman for generation of new stack.xml for the system.
Hope this will help you.
Regards,