Gaussian calculation - PCM model for IRC compared to gas phase?
Option 2 is the most scientific and rigorous. You should re-run the IRC in solvent again because the reaction path can be different from what you got in the gas phase.
Now, will it be different in solvent? Unless you are dealing with some exotic system, different reaction path with implicit solvation is unlikely (provided you have the same TS and minima with PCM). However, the reaction barriers may significantly change, which can cause two subsequent steps to become one single step (the TS between them forming a shoulder in the IRC). I have seen this happen.
What matters though is that different reaction paths can happen, so you should run the IRCs in solvent if you want to be sure of your result (also because you want to publish it).