Migration from SQL tables + Shared drive (documents)

Hi,

I have to migrate double digit of terra bytes of content from SQL table, and which contains related documents path where documents resides in a shared folder / network drive.

I have to use custom developed tool to migrate / move the content with the attachments to my document libraries.

My queries are,

1. Are there any tools available in the market to migrate/move this content SharePoint.

2. If custom developed tool, can i Use CSOM/REST API

3. Can I use powershell? One should run powershell scripts on the sharepoint farm itself. Cannot I run from outside the SharePoint Farm.

4. Suggest better approach if there is any.

- GEM