See this post of mine and the following 4 replies for a discussion of using products on the Elgin. I think you can safely use AE's LL, CC, or SS on them, but you're more likely to lose a little dye the further right you go. So far, I've only used LL and CC on them, but will try SS if they get dirty enough. I don't think you'll ever need to add color with polish. Cold Iron darkened his with neatsfoot oil, so that's always an option if they ever got too light from excessive cleaning, but I don't anticipate that becoming a problem.
As for various other leather products, I'd be very careful. Many contain ingredients that may unexpectedly darken or lighten them.
Thanks for the detailed reply. I'll probably pick up some LL for the Elgin and keep the CC just for my McAllister and other dress models.