I think you're getting a few things confused Biswaroop.
Firstly, HFS only supports one system of charachter incoding, MacRoman. If your korean charachters aren't there, then you can't use them.
Secondly, when I installed hfsutils, I didn't use mkhybrid (the hard links to the hfsutils application didn't work under cygwin, so I had to guess at what to call it. I never tried mkhybrid). Cygwin is a massive application (600Mb) if you install all of it, which you probably don't need to do, so I'd suggest trying to get the setup.exe application again. It will download the relevant parts as needed depending on what you choose to install. You'll need gcc, binutils, make and cygwin (and win32api) to make hfsutils. Just select the whole compiler section in the setup options. The thing to remember though is that cygwin/setup.exe is a symlink to cygwin/latest/setup.exe, so if you're in an ftp browser, and you have problems with the main setup.exe, get the other one. To get cygwin goto http://cygwin.com/mirrors.html and pick a mirror (such as ftp.mirror.ac.uk) then go to the latest directory, et voila.
Thirdly, every filetype available on a PC is availiable on a mac, as long as a compatible application is avaliable (so include all M$ applications and adobe applications, and any other company thats any good). The finder uses a long (4 bytes) to store the application type. There are therefore at least 64*64*64*64 possible applications that use normal ascii for that. Have a look at netatalk for a list of some avaliable (the etc/AppleVolumes.system file contains a list). On my system there are about 250 extension to Finder Tag conversions, but what most people do is run a netatalk application to regenerate that file, based on what a particular system has used. Remember the Finder Tag referes to the Application that made it, not the file type, so things like .wav .jpg .gif may have several different tags, one for each application that can create them. You need to pick the one that your system uses.
A Hybrid CD contains 2 different partitions, only one of which will be visible on a non linux system (I belive). The difference being ISO contains MBCS (or atleast DBCS) filenames, and supports file system 'extensions'. I don't know what the standard is for the HFS part of that. I'd guess you can make the HFS partition HFS+, but apart from that, don't use it unless you really need forks.
You need to decide whether forks are more important than filenames, and decide what you're going to store where I think. Unless forks are a MUST, ISO is easier.
Simon