Yes you can, but don't remove them until you are sure that you have the initial key or QR code in your possession. If you do not have that, the easiest way is to go into each account and disable 2fa. You will very likely need the code from Authy to do this, so make sure you do not delete it from Authy yet. Once 2fa is disabled, turn it back on, but this time add the account to Google Authenticator. Validate that it works using Google Authenticator before deleting the account from Authy.