it safe enough to leave the unused D+ and D- pin as no connects..
1) It is fine to leave the PWM O/P open cct. The ADM1030 also allows you to
disable a PWM output in the Config 2 Reg, Bit 0 for PWM1 and Bit 1 for PWM2.
With comment that you may need to consider protection circuitry is the pin
connection is accessible by the user.
2) If you leave the diodes open cct then a bit gets set in the Status Reg, No
INT is generated. Monitoring of these channels is automatically disabled when
the diode is open cct (Bits 5 and 6 of Config 2 Reg)