Here, again, Sir, you are mixing your mythos or outright lying. Lincoln had his own "Central America plan" which he personally laid before a delegation of leading blacks. It had nothing to do with building a canal, but had more to do with coal. Herein, you are referring to the very dubious Panama Plan of Gen Butler (the canal plan, that Butler claims to have introduced to Lincoln in April, 1865). Only Butler is the source for this Panama plan. Two entirely separate plans which you have just mashed together. Just trying to be objective.
I don't see where the specifics of various plans are terribly relevant. We can grasp what we need to know simply from the general outline.
Lincoln favored getting black people out of the USA in any manner of which he or others could contemplate. He was apparently interested in doing this up until he died.
You don't like this because it casts a blemish on his legacy. For me it is simply another means of revealing that Lincoln was not at all the saint people have made him out to be, and that he cared more about controlling Southern whites than he ever had concern for blacks in general.
You don't like it because Lincoln's efforts to get them out of the country undermine the belief that concern for them had a significant role in why he fought that war.