Hi Linjo,
on my side, that was not the case. Everything was resolvable.
But, I decided to make another (4th) installation, and in my last attempt, I named all appliances using default names (the one from documentation). Furthermore, I configured IP addresses in the order that is displayed during initial VAs configuration. Using these values, installation passed without issues.
To summarize:
in my first attempts, I named VAs, using names like: horizon_cfg.mydomain.com, horizon_gw.mydomain.com, ... and giving IP addresses in some order that was random.
In my last installation attempt, I give names to VAs, and IPs in the following order:
configurator-va.mydomain.com first IP address
service-va.mydomain.com
connector-va.mydomain.com
data-va.mydomain.com
gateway-va.mydomain.com last IP address.
I think that IP order should not cause any issues, but naming convention might cause issues that I had in first installation attempts. On the other hand, I didn't find any indication in Horizon documentation, that I cannot use my own names for VAs.
So, for now, I can move on with my evaluation.