Resources.dll has most of those entries in. The animation in the start screens while compressed into a THN file is actually using LUA, so if you're a dab hand at that, go for it. Start screens are easy to change, otherwise what Dwn said
One thing I did wonder about is do the THN files have to be compressed/compiled in order to work in the game? - I am assuming yes, which is not a big issue, just a bit more time required to compile/compress the files. I'll have to see if I can get hold of the source code to decompress/decompile and compress/compile those files so I don't have to do it 'manually' for each script.
I have the source code for reading/writing resource DLLs - that has saved my about 40+ hours work, and major headaches having to record which IDs I used for each string & infocard.
To give you some numbers - I have approximately 1200 custom name resources so far, and about 800 infocards (seeing as ships require 3 custom cards each - i know it's 4 in total but the stats template one (ids_info2) is the same for all ships so can be referenced by all).