How to get Exchange 2016 user visibility of existing Exchange 2010 Public folders in an Exchange 2010 server farm with CAS and Mailbox roles on discrete servers?

I have an existing Microsoft Exchange 2010 farm consisting of a separate server with the CAS role (MAIL01) and a separate server with the Mailbox role (HSMAILDB01).   The site makes extensive use of public folders.  The public folders are housed on the HSMAILDB01 with the mailbox role.   I just created a new Exchange 2016 server containing both the CAS and Mailbox Roles (MAIL02) in that existing Exchange farm.   Everything is fine and I can send and receive mail to/from both servers as well as to/from the internet.  OWA works fine (old and new).   The mailbox migration is slated to take place over time in phases.   I need to make public folders from the Exchange 2010 server visible to the 2016 mailbox users until everyone is migrated.  Then I need to migrate public folders to 2016.

I have done this before using this Microsoft article: https://docs.microsoft.com/en-us/exchange/configure-legacy-public-folders-where-user-mailboxes-are-on-exchange-2013-servers-exchange-2013-help

However, previously the Exchange 2010 server had both the CAS and Mailbox roles.

This Microsoft article says I need to add the CAS role to my HSMAILDB01 Exchange 2010 mailbox server to make this happen.

My question is if I add the CAS role, to the Exchange 2010 mailbox server, what effect does that have (if any) on the existing CAS server MAIL01 and orignal OWA and Outlook users still on the Exchange 2010 servers, etc?   Is adding this role purely a back-end function that won't disturb the existing, happy Exchange 2010 users running Outlook and OWA through MAIL01?   I can't disturb them at this time in any way other than perhaps a scheduled Exchange 2010 server reboot.  Secondly do I have to fully provision the second CAS server on the original Mailbox server to the point of letting people see it from the internet with a separate name, etc. or is it solely a back-end function so the Exchange servers can talk to each other and pass information to each other?

Thanks!