that sound great 4 garand 2 carbine for paratrooper and 3 for ranger will do
That's exactly was my idea: 4 Garands plus 2 M1 Carbines for Paratroopers (like in the "Band of Brothers" and - which was pretty surprising! - real loadout of the Paratrooper half-squad) and 3 Garands plus 3 Thompsons for Rangers (pretty close to the "Saving Private Ryan').
Editing the abp file should work, unless a patch messed that up.
I followed...I believe it was Eliwoods' abp edit tutorial and did this same thing in one of my mods because I had the same gripe with the weapon choice.(I was able to mix carbines, upgrades, and m1 rifles by making a whole different paratrooper entity with a different weapon and then messing with the sbps squad loadout.)
I did a similar thing for Sappers, ended up giving them enfield sten mix
All described can be done, except for one thing - both Rangers and Paratroopers visually run with empty hands even after editing the *.abp.