Are there pre-built aspects of Haiku I can just download and install to replace portions of BeOS and slowly turn it into HaikOS (or Beku), as I wait for it to be fully transformed into Haiku!
If not, where is the best place I can go to be given step-by-step instructions on what to get and download and do, in order to slowly transform BeOS into the new Haiku?
Thats very possible. You can for an example download apps, kits and drivers to replace them in BeOS.
Some time ago we had something called a build factory. The build factory provided us with updated bits and pieces of Haiku, but the site is down, and has been for a very long time. Your best shot to get Haiku-parts is probably BeBits (some of the stuff there may be a bit outdated), and/or compile them out of the source tree yourself!