But the actual conspirators plan was to murder many of the high ranking officials of america. THATS the question i am posing, which would include grant, and for a short while the country would be tremendously de-stabilized, and the south could gain a chance to rise again.
They couldn't murder more than a handful. There just weren't enough of them, it was a very small group. And there's a lot of scope for things to go wrong. Note that they targeted three men, and managed to kill only one.
The best chance to get Grant would be for him to accept Lincoln's invitation to come to the theatre, so that Booth has a chance at both of them. However, if Lincoln and Grant are both in the theatre, it is likely to be better guarded.
If they do get Grant, the next officer in line is presumably Sherman. But he is no more likely than Grant to get vengeful. He received the news of Lincoln's murder while talking surrender terms with Johnston, but his only reaction was to place nearby towns off limits to his men, just in case any of them
did get ideas about private revenge. The same would probably hold good for a majority of senior officers. The leading Rebs are old comrades whom they probably knew at West Point, and with whom they feel far more in common than with even the most loyal freedman. None of Booth's conspirators belonged to that circle (any more than Major Wirz did) so there was no problem about hanging
them, but it was never going to go any further.