I decided to try to install VNC server on Mac classic and try how it goes.
I installed chromivnc server 3.40a5. The only thing after the installation, or rather I should say unpacking, was to copy vncPatches file to Systems Folder/Extensions and restart my mac. Afterwards, I started vnc server without any problems, and that was it. My vnc server on Mac 8.6 was working.
Nevertheless, I have to admit, that it is considerably slower with comparisons to more newer version of vnc for Mac X, or Linux. However, it is enough for fast, small work on Mac OS 8.6.
Below image showing Kubuntu with VNC connection to Mac X Tiger and Mac OS 8.6