... no resolution outside of setting up a private DNS and that's a mess in itself.
Unfortunately you didn't tell which operating systems your LAN clients use. If you are using Windows you could activate and use NetBIOS name resolution instead of DNS, since according to the
VNC knowledge base VNC software does not directly perform any type of Name Resolution, but simply asks the operating system to resolve names on its behalf.
You can test if NetBIOS name resolution works by typing
nbtstat -a <COMPUTER> within a command prompt, where
<COMPUTER> has to be replaced by the name of another computer within your LAN (lowercase "a" is significant, uppercase "A" has a different meaning!). If successful the command shows the NetBIOS name table of
<COMPUTER>, and then typing the command
nbtstat -c would reveal the IPv4 address
<COMPUTER> was resolved to via NetBIOS name resolution.
PT