Virtual warehouse is the name given to the compute clusters used by Snowflake for query processing

Once a share has been granted to a consumer, and the consumer has created a read-only database on the share, all new objects added to the share by the producer automatically become accessible to the consumer

Correct. Snowflake has been designed from scratch for the cloud.

NULL values are stored as literal "null" in VARIANT columns. Please see below link for more details https://docs.snowflake.net/manuals/user-guide/semistructured-considerations.html#null-values

Transient and temporary tables don't have any failsafe, this is done to reduce storage costs for temporary and transient data. https://docs.snowflake.net/manuals/user-guide/data-cdp-storage-costs.html#temporary-and-transient-tables

All of the are valid examples of the metadata that Snowflake stores for micro partitions https://docs.snowflake.net/manuals/user-guide/tables-clustering-micropartitions.html

Incorrect. The multi factor authentication is not enabled by default.

Extra Storage is used when the data in the cloned tables are modified or a new table with data is introduced. There is no setting called CREATE_COPY If you don?t have privileges you can not clone an object https://docs.snowflake.net/manuals/sql-reference/sql/create-clone.html#general-usage-notes

Micro partitions are generally between 50-500MB before compression https://docs.snowflake.net/manuals/user-guide/tables-clustering-micropartitions.html

Failsafe retention for permanent tables is 7 days https://docs.snowflake.net/manuals/user-guide/data-failsafe.html