Actually, some issues might arise after a reset of the X-form, or they might not. It depends on the specific situation. As I mentioned in the guide, an intermediate export-import to SMD can be helpful. And at this stage, something similar to a reset of the X-form also occurs (only even more so).
For example, I'm currently importing an Orc from Heroes 6, which has 80 bones. A rider from Heroes 7 has around 150 bones (including the mane, tail, and tail on the helmet).
In Heroes 5, the Knight hero has a lot of bones because there's the horse, saddle blanket, and flag (one flag seems to consume around 30-40 bones), as well as a cloak, squire, and a small flag on the squire's pole. I think it adds up to around 250, and I need to add a few more and combine different versions (for example, Duncan's horse has bones for the mane).
Added 5 minutes later
Titan has 102 bones, I just checked. It's just that he has a skirt and some kind of thing on his arms that sways.