Offline Editor Ion layout? And Highlight

To clarify: We want to select our moving light 201, and have it at the intensity of the cue it is in, have everything else out, and be able to press go while retaining the moving light's parameters (including intensity) and all other lights stay out

yes, you found the right place :)
in the shell of your offline editor, does the logo say Element or Eos? if it says element, then you're in element mode. click on the small font below the logo that says change console mode. then choose Eos.

remdim is a way to do something with all active channels that were not selected in the same command line. Chan 5 @ 50 RemDim 03 Enter, will bring channel 5 to 50 and all the other channels that have now an intensity > 0 to 3. now you can either go on with other commands or you can use next and last to select channels and change them. this next/last thing is a bit like a mini-highlight mode and as such is a bit tempting. i personally use remdim to remove other levels, but after that i continue with other commands, not with the mini-mode.
highlight is a way to bring each selected channel to full. if you activate Highlight RemDim in setup (by setting a value in %), highlight will not only bring up the selected channel, it will also suppress the unselected ones. you can also, instead of using the setup option, type remdim and a level each and every time in the command line that you use to start highlight mode: Chan 1 Highlight RemDim 03 Enter.
i think Highlight Preset is worth mentioning: default behaviour of highlight is to bring up intes and to remove color and gobos(?). if you don't like that, you can create a preset that in setup you make the highlight preset. in this preset you can define for each channel separately if e.g. you just want to increase brightness but leave color as is.

regarding your last question: no sorry, that doesn't seem possible, but i don't know if it's a bug or a feature...