What you would also need to consider is the costs associated with owning a house: real estate taxes, utilities, maintenance (landscaping, painting, minor repairs, security, pest control, pool, etc), Home Owner's Insurance, plus major repairs such as plumbing, masonry, roof, electrical, Central AC, etc. Within the same decades you would own DVC, you can expect to replace all appliances (kitchen, laundry, TVs, etc), furniture, etc in a house. Of you are considering renting the house out when you are not there, you need to factor in higher maintenance & replacement costs (higher use = lower lifespan), as well as more frequent refreshing/replacement of décor, & replacing linens, cookware, etc. There is also the likelihood that, since you don't live nearby, you would probably be best off hiring a property manager.
These numbers don't even include the costs incurred for transportation (Gold APs are available to both FL residents & Blue Card DVC Members, so that is a wash).
We had looked into buying a house there (only for vacations & perhaps rentals, we have no interest in actually moving to FL), but found the costs & headaches wouldn't be worth it to us. This isn't to say others don't prefer owning a house there, but that we prefer the lower overall costs, responsibilities & risks with DVC, and the included transportation, superior customer service, quick access to parks, etc included with any WDW resort stay.
You might want to consider getting enough points for a 2-bdrm since you said you are only 6 people......or you could get enough for a 2-bdrm & a studio, which would still be less than a Grand Villa.
