Yuzu is most certainly going to get NHK, no doubt about that. NHK/IDF is also just under 2 weeks apart, same scheduling as SC/NHK, so I think SC/NHK is more possible? SC is more convenient and certainly no jetlegg for him, and NHK is almost 4 weeks before GPF which gives him plenty of time to train and make adjustments to the programs. The only problem is where to put Shoma, Shoma can also do both SC/NHK but I don't think JSF would want the top 2 contenders in the same GP 2 times in a row.
One possible option is they both do SC and shoma either do the new gp back to back or do the IDF. Now if Nathan also gets IDF, I don't know how the Feds are going to sort this out since Shoma and Nathan are not supposed to be in the same GP. However, I do believe there are some leeways n loopholes so they can put the 2 together. They have done it before with Yuzu n Takahashi in 2012. Maybe they will do the same with Shoma n Nathan this time too?
Another option is yuzu gets SA/NHK, so shoma gets SC/NHK, and they willl only meet each other in NHK which is still better then competing 2 times in a row together. But we don't know if the US Fed wants to invite yuzu at all