Reddit reviews The Outlandish Companion (Revised and Updated): Companion to Outlander, Dragonfly in Amber, Voyager, and Drums of Autumn

Do you have a copy of the Outlandish Companion? It provides most of what you are looking for, although you'll have to look stuff up instead of having a side-by-side. You'll probably want Volume II since you're just starting The Fiery Cross.

They are nice to look at but monsters to try and read from - the hardcovers are BIG and heavy books. So, if it's just for looking at, then sure.

Those two companion books I listed - those are full of neat things like how to pronounce things in Gaelic, family trees, essays about historical medicine and other research she did - also lots of pictures and such, so you'd want hardcopies - link

https://www.amazon.com/Outlandish-Companion-Revised-Updated-Outlander/dp/1101887273