They're not going to let you reserve 1 room for a party of that size. The most that you can legally put in a room at a value resort is 4 people, plus one child under 3 years of age. Disney doesn't bend on the room occupancy rules, believe me. They will ask for the name of every person staying in the room, and they will require you to book a second room if you want to stay at a value.
Besides, the beds are tiny. It's hard enough to fit two people in a double, but two and a toddler is going to be nearly impossible. Even if you could, that still leaves you with a twin aerobed and a pack and play, and I doubt that there's floor space for both. The rooms are very small.
For your group, here's what Disney will let you book:
- A family suite at All-Star Music (sleeps 6 plus a baby).
- A cabin at Fort Wilderness.
- A two bedroom villa at any DVC resort.
- Or, two rooms at any resort.
Some might ask, why not just sneak in the two extra people over the occupancy limit? Leaving aside the matter of fire codes, only those whose names are on the reservation will receive a resort ID. Without a resort ID, you can't attend Extra Magic Hours at the parks, which are one of the major perks of staying onsite. Those who are not on your reservation will not be able to use Magical Express, the free bus service from the airport. If you intend to book the dining plan, two members of your party won't be able to use it.
For me, the biggest problem would be, 7 people in a 260 square foot room, with double beds and one bathroom. Honestly, if all I could afford was one room at a value resort in that situation, I wouldn't go.
If two value rooms would bust your budget, you might want to check into off-site resorts. The odds are that you'll find affordable, comfortable accommodations for your party.