Dataset creation in DirectQuery mode and the Snowflake data source

I am trying to use the API to create a dataset with relationships and measures with a direct query connection to snowflake.

However i have reached different limitations with both th epublic and embedded API's that prevent this.

Public API: Allows the full features dataset creation, but not in DirectQuery Mode. Also unsure how to create connection strings for other types of data sources like snowflake

Embedded API: Doesn't allow the new dataset creation. And only supports direct query for Azure SQL/DW sources.

Question 

1. Is my understanding correct? Can i do any of this now?
   
   When can i expect
2.  embedded api to have the new dataset creation capability? 
3. support for  direct query with dataset creation?
4.  support for creating/updating snowflake connections using the api ?

Thanks!