7MTT with Snapmirror Relationships

We have 2 old 7-Mode systems (Main and DR site)

Use 7MTT 2.3.1

7-Mode systems is 8.2.3

CMODE 8.3.2P1

We have CMODE system only on DR site now, CMODE system on Main site will be shipped later (next month)

Now I created Project in 7MTT and added Main 7-Mode and DR 7-Mode + CMODE on DR site

Now I have Secondary subproject where described Volumes with Snapmirror relationships and I run Data Copy from DR 7-Mode to DR CMODE)

Primary subproject now is empty and I can't edit this subproject until Data Copiyng ...

Question:

Is it correct project? May I add to primary subproject CMODE on Main site later (which will be delivered later)?

Or need both CMODE systems up and running BEFORE any Migration?

Or

Do we have option Create new project later and add Main CMODE with Snapmirror relationships which already migrated (Main 7-Mode to DR CMODE)?