My ls plant compiled!! The RCG code can now be found in /opt/rtcds/rtscore/tags/advLigoRTS-2.5. I uploaded a copy of c1lsp.mdl onto the svn.
The weird "failed to connect" error was due to the fact that I named my inputs the same thing as my goto/from tags, so the RCG got confused. Once I renamed my inputs, it worked! I'm not sure what happened to the original "not enough parts" error; it didn't appear a single time during the rebuilding process. Anyway, I made the PDH block much neater, though the lines between PDH and ADC are looking wonky (this is purely an aesthetic problem, not a "oh god my simulation will DIE right now if I don't fix it" problem). I'll fix it in the morning; screenshot attached!
The original c1lsp was kind of sad. I updated it extensively and brought it into the modern era with color. The original c1lsp.mdl should also be on the svn. Tommorow, I'll get started on figuring out how to get LIGO specific noises from white noise.