How do I merge two accounts? And will the gameplayinfo from BF1 get wiped?

Hey, so if you wish to have your accounts merged you need to contact EA support, here is link which might be handy :

https://help.ea.com/en-us/help/faq/contact-ea-help/

And here is another about account merge :

https://help.ea.com/en-us/help/account/linking-accounts-and-persona-transfers

Sad to say but according to this you will probably loose your online progress.

Hope that helps.