A suicide hub just means there is no lockring. You are not going to be able to install a lockring on your hub because it is only intended for a freewheel. Its easy to thread the cog on tight enough that a lockring is unnecessary (google "rotafix"), although there is a possibility that the cog could unthread when backpedaling, hence the term "suicide". Its not really all that dangerous if you have brakes, though it is a bit janky. A new wheel (or rebuilding the old wheel with a track hub) is always better.
You need to decide what you want to do with the front of the drivetrain first...that will determine your chainline and what your options are for the back end.
Every conversion is a unique adventure!