The most versatile DI box is a passive one since you can use it in reverse (which is only relevant if the DI doesn't do 1:1 voltage conversion but something like 10:1, a "natural" 20dB "attenuation"). However, this versatility is not needed for your applications here.
The difference between an active and a passive pickup and an active and a passive DI is that the active component can produce a reasonably high gain on a low impendance sink. A passive pickup produces high gain on high impendance, a passive DI converts to low gain on low impendance.
So with an active DI, you can use lower gains on your soundcard input (switching to the line input is not an option if you want to use phantom power for the DI, though). In general, amplifying at an earlier stage in the signal chain makes your signals more resilient to noise. However, if the DI amps are of lower quality than the soundcard preamps, this might negate the theoretical benefits, so a cheap active DI might not actually help.
A passive DI will tend to attenuate low frequencies. For a guitar, this will not make much of a difference. It might be a bit more noticeable for a bass guitar.
All that being said: the Scarlett 6i6 has instrument inputs (high impendance unbalanced). I don't see physical switches on the product images, so I suspect the mixer application to be able to switch the line inputs to "instrument mode" by software. Unless you have inordinarily long cables in play, I don't really see a point in using a DI at all here.
