Patrick, you're spending too much time in the forums. Get back to work!
@claudi8b6 Gotta go static. Gateway does not have a DHCP server. (optional why: https://phabricator.whonix.org/T239)
Patrick is saying to remove whonix-specific features from gateway (like firewall) so you can test connectivity without complicating factors. (for example, to ping).
If you had to flip interfaces around at build time, then you might have missed some config files. grep for those. Otherwise, it's just a standard network config in ws-host. use debian GUI. also, make sure internal network eth has proper settings in gateway.
IIUC it can but not by default. There are no uwt wrapped applications or pre-configured socks proxies in a ws-host. Host traffic will travel through transPort by default.