Griss needs STR 4 for Heavy Hand. That tends to limit her effectiveness as a true agility build. Instead, what most players end up doing is giving Griss STR 4 and whatever weapon works best for the situation, regardless if it's 1-Hand or Light.
Note that Griss can also learn Infantry Training, which requires a 1-Hand weapon.
Don't forget she can get a STR or AGL belt. If you give her the Superior Belt of Might, you can give her the Explorer Gauntlets. That gives her a bonus to her STR and AGL plus a decent armor boost. If you do that, you can give her AGL 1, and let the boost from the gloves give her AGL 2, which results in the damage increase with hand weapons. Then at the Ark, the AGL 3 gloves give her a final AGL 4. That system allows the best versatility in weapon types well maxing the benefit from equipment.
Note, because of the AGL 3 gloves, the AGL 2 belt is outperformed for all classes by the end game. In contrast, there's only 1 STR 3 belt in the game.
Giving Griss END 4 to learn Body Development might be a bit of an overkill. Companions pop-up pretty quickly when killed so for most of the time, her reaching 0 HP isn't a big deal. However, for crowds or bosses, I can see the desire to make sure she stays in the fight a little longer (esp when playing with a Rogue).
If you are going to give her END 4 and STR 4, you might as well give her Body Development 2, or 3 if you are really trying to help her be a HP tank.
The downside is that heavy investment in those skills will reduce other skill enhancements.
If you want to make Griss defensive, then maxing Shield Expert is recommended, give her at least 1 point in Fury (that will also pair well with a higher max HP), and maybe keep her at 1 point in Cleave. That should free up skill points to max Heavy Hand and Body Development. For your build idea Fury is likely better than Cleave as it pairs well with a higher HP.
