MarkT:
No, 7 resistors and 0V and Vcc are among the valid 8 voltages. Fig 1-3 in datasheet.
Yes they are, but the allowed range for the first/last rows in the table is bigger.
Think though: With 7 resistors the first voltage in your chain would be 1/7 VDD.
At VDD=5.5 that's 0.7857V - nowhere near any of the target voltages in figure 1.3 (column V2).