Recorded is recorded... There is no way to "add" something to a finished recording. By default, all recording is pre-processing, which implies that you can change this setting. per channel (check channel settings).
You can transfer a recording scene from SD card to Studio One. Look for the ".scn" file and change it to ".scene". Then it can be loaded in Capture (computer) and I think also in Studio One. I never do this because processing settings of a live concerts do not really have something to do with the processing in a DAW. Important is what you HEAR and what your ears say what needs to be done.
Studio One has the same Fat Channel as the mixers. The Fat Channel is a stock plugin and can be equipped with the Fat Channel "plugins". Basically it should be possible to use exact the same tools, but you will always hear a difference. Live and Studio are two different worlds.
