Yes on both counts. The Data Migration Framework is definitely not the
Both Scribe Insight and c360 Import Manager can be good choices for a
one-time data migration involving custom entities. They both use the CRM SDK,
so they are considered to be supported by Microsoft.
Unless you're a serious programmer, or have access to one, trying to build a
data migration solution yourself using the CRM SDK is going to be hard.
You can access the CRM SDK through the Microsoft website. Just search for it.