Probably not in any major way. Based on the answers, you’re unlikely to see a noticeable sharpness improvement just from switching between these Nikon and Canon full-frame bodies and pro zooms. Your current Nikon setup is already very strong for portraits.

For family portraits, the 70-200mm is especially well suited because focal lengths around 105–120mm on full frame often give a flattering perspective when you stand farther back. A 24-70mm can be useful, but it isn’t automatically better for portraits.

Color differences between brands are usually more about JPEG processing, picture style, white balance, and editing choices than about one brand having inherently better color. Proper white balance and a suitable portrait profile matter more. Avoid overly punchy settings like Vivid or Landscape for portraits; Neutral, Portrait, or Standard are generally better choices. A white balance card can also help with consistent skin tones.

In short: don’t expect a dramatic difference in sharpness or color from this switch alone.