The A-pose for the 4.8 skeleton makes things more difficult. I am not an animator but I’ve successfully used retargeting for existing and custom rigged characters with the T-pose. Most (all?) of the animation packs on the marketplace are T-pose reference too. I tried doing the same with the new skeleton and while it probably can be done, it seems inherently more difficult. Especially for someone without animation experience or training or resources to get someone like that on team.
I hope Epic will consider providing a skeleton with both reference A-pose and T-pose.