We still do not have that pose in CC. We have a T-pose (base pose for weighting CC3 and below characters), but not a Bind Pose. It is a base A-pose for weighting cloth to CC3+ avatars.
You might get away with weighting in A-Relix pose, but for complex garments, that is certainly not enough.
If you bring something *heavy* from Marvelous Designer to CC, you have to simulate that garment first in Bind Pose in MD and then later on Transfer Weight in CC in that same pose, saving yourself a lot of hassle.

Moreover, if you want to weight paint outside of CC, or just fix weight paint (when CC smooth brush just freeze on dense mesh), you sure must have your Avatar in Bind Pose initially.
Or else, taking it to Blender would cause trouble, while pose would switch from Relex (or any other) to Bind as soon as you import and mesh gets messed up even more.

Anyway, I converted this pose from Blender this afternoon.
Drop it into the default Motions in iClone and CC to have it handy.

Updated on 7.31.2021
Updated to version 3 on 6.17.2022  Download from Google Drive: https://drive.google.com/file/d/1OyV-hdqMFUwOdnwUZ-DOwW7QSuZBCRxj/view?usp=sharing