Here we go... and please remember I'm talking about a whole house, and not one room so everything isn't going to match perfectly. Ok? Cool.
First, I think a color palette of pale grays, blues and smokey teals will instantly transform the feel of the house. I'm a big fan of the West Elm and Pottery Barn collections at Sherwin-Williams, since someone has culled the bajillion options for you already. Then, to add some more personality, Michelle could add some wallpaper on accent walls or powder rooms, and bring in printed fabrics for curtains and throw pillows.
In areas where there is wood, tile, or just carpet that she'd like to cover up, I think a fairly inexpensive geometric rug from World Market or Homegoods will add personality and be dog-friendly since you can send a rug off to be deep cleaned in a way that you'll never achieve with carpet.
Some rugged furniture will add a masculine element to the rooms, but not make it feel like a hunting lodge since it can be offset by classic pieces, colorful accents, and pretty nailhead trim. And since everyone in our family is convinced that we can indeed do it ourselves, I'm sure a painted vintage piece will make its way into the home sooner or later.
Overall, my main advice for people approaching a house from scratch is to set the mood with paint, and then start buying what's important to you and don't settle too much. It's hard when nice things cost a lot of money, but what you don't want is a house full of things you want to get rid of in five years. Luckily, you can inject tons of personality into a space with affordable art from Etsy and secondhand pieces that just need a little attention.
Good luck, Michelle! You know where to find me if you need more opinions ;-)