The answer depends on your needs, other band members needs, and the situation.
Personally, I don't think it makes sense to continue using a cab or even an amp with IEMs., but not everyone agrees. If you dig in to TalkBass you will find comments where the bass player preferred having a cab to either fill out the sound or provide some tactile sensation. You will also find comments were the bassist was fine without a cab, but other band members wanted him/her to use a cab.
As an audio tech, I normally prefer the bass to be plugged into a flat response DI. This connection means the bass player is free to adjust his/her amp without impacting the DI signal. I.E. I get a more consistent signal at the mixing console, and I don't have to reverse engineer whatever mojo the player dials into his/her sound.
You may think this does not make sense, but IMHO each signal should be processed discretely for different purposes and listening locations. That means you need a certain type of processing to get the desired sound on stage, and the audio tech needs different processing to dial in the desired sound for the main mix.
My opinion is a bit different when the bass player is relying solely on IEMs. IMHO, it is beneficial to have tone controls at bassist's fingertips, so he/she can quickly dial in a sound for the IEM mix. So an amp or perhaps a preamp/DI could be useful.
With more advanced mixing setups, this need may be eliminated. For example if the IEM setup allows the musicians direct control over their tone in the mix. However, if the bassist prefers a certain baked-in tone, some sort of signal processing may still be relevant. For example the bassist may prefer a certain amp and/or cab SIM.
Ultimately this is something you should discuss with whoever will be running sound for the tour. Something to keep in mind, live audio is often more about finding the best compromise rather than achieving perfection. Also, this is not a discussion you should expect to have on gig day, or even the first rehearsal day. Call and make an appointment to work things out in advance.
No idea how close the tone of the TH Preamp DI is to the TH amps, but something to consider:
Tone Hammer – Aguilar Amplification