How to transfer "mail for domain" from Google to Yandex?

Question

gmail

Greetings.
There are mailboxes that work through google servers aspmx.l.google.com. A certain domain (let's call it mydomain.ru) has a corresponding mx record.
Accordingly, users enter gmail mail with a beautiful name (a la [email protected]) through the web interface, chat there, chat in hangouts, etc.
There was a need to force mail to go through the Yandex server.
In this regard, there are several questions.

1. Will it be possible after that to go to gmail under the same access details, read old mail and chat in hangouts?
   
2. Is it possible to somehow load this old mail in outlook. After all, the postal address will not change outwardly, but the source of the letters will be different.
   
3. Will it be possible to write something to someone from an old mailbox?
   

Answer 1

1 and 3 - no
2 - yes