1. The product version is up to you. Usually it is used to defined different products for different releases of the SCAs, f.a. you define product for 720 and in it you define SCA Build Time dependencies for SCA version 7.20. However please note that the version of the product in SLD is totally up to you. You might define version 1 and still apply SCA of version 7.40.
2. DCs are not created, moved or handled in any way in SLD. DCs are created, moved and handled in NWDS once you have imported your Development Configuration Track. You define your DCs in the SC which is defined as "Developed" in CMS. (Usually this is your defined product in SLD)
Please note that you might copy, move DCs from Local Development to a track in NWDS. However by doing so you will copy only the code! The SCA dependencies are not copied and you have to defined them later. More info in:
Migrating Local Developments to a Centralized NWDI Environment (Developer’s Viewpoint)
http://scn.sap.com/docs/DOC-3204
Step 3: Copying Local DCs to NWDI Track SC
3. Last but not least, I would like to warn you that the following versions MUST be consistent:
. NWDS,
. Track,
. RunTime System.
More information explained in details with examples in:
http://scn.sap.com/community/nwdi/blog/2014/03/26/nwdi-vs-nwdi-content
and if you have access to service market place in this note:
718949 - Web Dynpro Application Compatibility WebAS SPx -> SPx+n