Looking to replace Web Application Proxy with KEMP for our Exchange 2019


Currently I am using Microsoft's WAP as a reverse proxy in DMZ for Exchange. 

WAP is very limited and I want to get rid of it as we don't use the ADFS component it has a dependency on, was going to try KEMP free edition to get started but have some questions for the community.

When I publish Exchange virtual directories through KEMP, we're looking to do this in pass-through mode and not do any pre-authentication, can that be done? Are the templates that are available for Exchange 2019 setup for pass-through? 

When publishing the required Exchange directories can we setup a redirect on the base URL to something else using KEMP?

Typically one would publish..

Now I know in Exchange you can setup redirect using IIS to /owa when someone hits the main URL (and we have this for internal users), but what I want is when someone visits the URL externally to be redirected to a completely different website.

Externally I don't want to publish OWA and ECP, on the KEMP side of things I want to redirect the user to a different URL if they hit the base URL.

So if user hits https://webmail.mydomain.com/ externally it would send them to https://someothersubdomain.mydomain.com/ while allowing me to publish the other Exchange IIS virtual directories and not have them affected?