This statement lead me to the idea to give the official launcher another look. Everything went nice while I launched launcher.jar directly, except, that it (even with %APPDATA% workaround forun through Google) continued to search for versions on my local disk(s), while I need it to search on the network disk (Z:\Share\Games...). This is needed as I am not willing to copy version after new forge version download on each workstation local disk again and again.
Further googling directed me towards using MinecraftLauncher.exe instead of launcher.jar. However I am completely unable to force it to see Z:\....\version\* versions of forge jars, even if they are present there. I am trying
start MinecraftLauncher.exe --lockDir "%CD%" --workDir "%CD%"
either with or without --lockDir it seems to behave same and revert to C:\...\AppData\...\version
As well the configuration flexibility seems to be worse than in previous launcher.jar solution.
As from your posts over forums I got impression you are officially related to Mojang, please, can you post step-by-step description how to do install on LAN Network disk Z:\<some_path>\Minecraft so, that no other paths, esspecially no local disk information, are needed to run multiple profiles (vanilla, modded, modded other way) so that it can be installed/updated once, used by multiple workstations? Thank you in advance.