The 1BRs at the following WDW DVC Resorts have sleeping places for five and allow five plus an infant under three: BLT, VGF, Riviera, OKW, SSR, AKV (except value 1BRs that allow only 4 plus an infant under 3). For any those, you can book five via the online reservation system.
The following 1BRs have sleeping places for four and allow either (a) four plus an infant under three, or (b) any five total (but no sixth infant) and you need to provide your own sleeping items for the fifth (if other than an infant) and need to contact MS to make it five (other than an infant): BWV, BCV, BRV.
CCV allows only four plus an infant under three.
The new CFW resort with the 1BR cabins have sleeping places for, and will allow, 6, but I do not yet know what its rule will be if you want to add a seventh occupant that is under 3.