The maximum clock frequency of the SN74LS165ADR is 10 MHz.
Yes, the SN74LS165ADR is compatible with 3.3V systems, but the input voltage must not exceed 5.5V.
To ensure proper latching, the clock signal should be high for at least 10 ns, and the data should be stable for at least 10 ns before the clock signal goes high.
The SN74LS165ADR can drive up to 100 pF of capacitance.
Yes, the SN74LS165ADR can be used in systems with multiple clock domains, but care must be taken to ensure that the clock signals are properly synchronized and that the device is not subjected to clock skew.