Solid connectionsstart with the basics.

SOA normally includes a primary server name, a responsible contact name, a serial number and timing parameters. The contact field is represented in DNS name form, so the whole text should not simply be treated as an ordinary email address.

No. It queries common types for the name you enter. Subdomains, service records and email authentication records require their own complete names.

These answers come from a recursive resolver and can reflect its cache, proxy settings or provider-specific features. Compare TTL and the actual configuration; a single lookup is not a global propagation test.