To match some of the expensive dog food vitamin and mineral content, would it be safe and effective to intermix with a home-cooked meal for my 25-pound dog, half a capsule of Healthy Resolve, which has a broad mix of vitamins, minerals and phytonutrients?

Here, you are following the same thinking as these high-quality dog food brands attempt to do in augmenting their choice of whole foods with an array of vitamins and minerals and other known nutritional adjuncts that are a key essential for human diets. So you are just mimicking that strategy, and if you choose a high quality and fairly comprehensive powder sold for human use, you can count on its purity and safety for use with your dog, by keeping with a proper ratio between human and the animal total body weight to reduce the dose level accordingly and prevent over-doing things. So this could be a very simple and cost-effective way to enhance any petfood that might otherwise be underpowered with respect to micronutrients.