I have a Titania I use to more or less the same effect, so I would say that sounds pretty good. Red covers her weakness to greens well (although it's specifically green mages that she's particularly weak to).
Depending on the build you give her, I don't think you need to further boost her Res any higher. I've always used a healer tank build (Special Spiral Aether now) and with Atk Smoke, it usually merely sufficed that she lived a hit because she heals in every engagement. Instead, I've found her Atk lacking much too often, if you can find a way to boost that.
As for Chill skills, I think Spd would be better because she lives or dies by doubling with Flashing Blade. I've tried it on my support Setsuna and that worked well. She's tanky enough to not have a problem with too much things, and mages tend to have less Atk than physical units anyway, dodging the Chill. Although it may be that Chill Atk is more useful in brigade maps, I wouldn't know.
