Ok, i will try to explain the layout of the 2das in general and the featgain/classpowergain.2da in specific... hope my not-so-good english and my rather nonexistant teaching/explainingskills will not make it impossible to understand it ;-)
As the name says it is a 2dimensional arry, or, in noncomputersüpeech, a table.
The first (from teh left) column is the the index, which has no real meaning (beside inengineuse), I think it is clear howto add new lines etc. ;-)
The line above are the names, in case of the featgain.2da theese are "label" (which is equivalent to the level in this 2da), *classname*_reg and *classname*_bon. I don't know what the _bon-columns do, but they aren't used anyway, AFAIK.
The reg-column specifes how many feats a char can chosse when he reachs this level, for example,
0 1 1
Means that a Soldier can choose one Feat at Level 1.
Now if you want that a Soldier can choose 2 Feats at each levelup, you have to change all noumbers under the sol_reg to "2".. Simmilar, if you want that a Jediguardian can choose a feat every level, you have to change every entry under jgd_reg into a 1 . And if you want that a combat droid (HK-47) gets 2 feats at level 10, you have to go to the label 10 (or index 9), and then go on that line til you get to the column of drc_reg.
Claspowergain is the same, except that there are only 4 columns (label, jcn, jsn, jgd).
As for making all NPCs spellcaster and Lightsaberwielders... I'm almost sure it is possible todo that, but it wouldn't easy...
First you would have to set the class in the classes.2da to a spellcaster, change the forcedie (the amount of base-frocepoints they get per level) and give them a spellgaintable (you could simply reuse one of the original tables, but then they could use the force from the beginning...)
So you have to add a new coulmn in classpowegain, which should "0" gain until you get to the level at which they shoudl be able to use the force... (maybe up to level 9, at level 10 2, and then at level 11-20 1)
That *should* allow them to use the force, but doesn't give them the ability to wield sabers or the special jedifeats. For those you would have to edit the feat.2da, or to be more specific, you would have to change the values of scd/sct/sol_list and _granted of theese feats. For example, if you want that Soldiers, Scounrdels and Scouts can use Ligthsabers (and have Lightsaber Profiencie, as this is needed for wielding Sabers) at Level 12, you have to go to the entry under label which reads "WEAPON_PROF_LIGHTSABER" (index 43), and then goto the columns "scd_list", "sol_list" and "sct_list" and change the value from 4 ("can't get it", AFAIK) to 3 ("will be granted at levelup"), and "scd_granted", "sol_granted" and "sct_granted" to 12 (which means that it will granted to every Soldier, Scout and Scoundrel at the Levelup to level 12).
If you then want to allow every Scd/Sol/Sct to get Lightsaberfocus, you have to change the entries under "***_list" in the line of WEAPON_FOCUS_LIGHTSABER (index 36) to either 0 or 1 (I'm not sure about which one, as it isn't documented...).
as said above, this *should* do the trick... but as I haven't done any experiments, I garantuee for nothing ;-)
BTW, the feat "Force Sensitive" only means that you get 40 more Force Points, AFAIK, and has nothing todo with beeing a jedi *g*
Hope that helps (and that you can make sense of it, if something is unclear, i will try to explain it better...)