Circuit for switching LED with minimal impact on digital signal
Any transistor will work. If you need 7 transistors, using transistor array is a good choice.
Note that your above circuit will turn on the LED when the input in a positive logic (~5V), however, ~CS pin selects the chip with low voltage.

Consider using PNP transistor switch that turn on the LED with low logic input (~0v)



R2 limits the base current. Make sure the transistor turn on when input voltage is low (&lt;2v), but the transistor is not turn on  when input voltage high (>3v). With this design, base current approximately -0.13 mA when input connected to 0v.

Alternatively, you may use a hex buffer 7407.