30 lbs would be pushing the upper limit for almost all frameless packs (though I'm not at all familiar with Camelbak models). If the weight truly is on her hips and not shoulders you've packed it well and it should work. However, she should test it for at least several miles because the bouncing action can cause the virtual frame to buckle over time, reducing torso length.

23 base sounds like a lot for a first trip. Your wife is likely tougher than mine, who just went on her second trip. She can't do uphills very well so the second day which was mostly uphill I carried her bag and pad as well so she had maybe 9 pounds on her back. She was about 13 the first day (with 1 L water).

I'd caution you not to take what she WANTS, but what she NEEDS. See that paper I linked or check the articles here.

The heat in the canyon is a butt kicker for some people. I like it but it wilted my son who normally wears long pants and a hoody in our hot, humid summers. As the video shows, we made it the 14 miles UP in the same time it took to go down. We started down at 6 AM, and I figured we'd easily be done in 6 hours (just over 2 mph avg) but it took him 8.5. He didn't want to stop (I was keeping close eye on him). We left Bright Angel at 3:10 AM and made Cottonwood in 3.5 hours, siesta most of the day under the tarp and then decided to go ahead and leave after dinner when sun was beyond the walls and took 4.5 hours to get back to the rim.