According to the announcement, exceptions may be granted if a party member can prove they joined “for the purposes of obtaining employment, food rations, or other essentials of living”. I believe Nepalese leaders could fall in this category.
In coming days, The US would definitely reject visa for any communist leaders and its cadres. The US always bend laws and rules as it comfort them and to the best of their needs. They are leaders in double standard policies, who knows it could be just aimed towards China?