Characters Natural Flaws

Characters should have flaws or else why would we read about them and root for them.  A character who is perfect has no where to go.

A major flaw I find this weekend is guilt.  Guilt because my home was spared from the flooding in the northeast simply by the circumstance of where I live and other peoples' homes were not.  In what way could this guilt pertain to my characters?

In President Lincoln's assassination, did the people he had asked to go with him and Mrs. Lincoln to Ford's Theater feel guilty afterward?  On April 14, 1865 the President went to the War Department as his usual visit and asked the Secretary of War Stanton to let him have his chief aide, Major Thomas Eckert to escort him and his guests to the theater.  Stanton refused saying they had important work to complete that evening.  Major Eckert refused under the same pretense.  They did not stay at the War Department and work; instead they went home.

General Grant had accepted an invitation from the President to join him and Mrs. Lincoln at Ford's Theater on the evening of April 14th.  Why then did he leave town unexpectedly?  Perhaps Mrs. Grant, who after being accused by Mrs. Lincoln a few weeks prior of having designs on the White House, changed her husband's mind.  They left the afternoon of the 14th to join their children in Burlington, NJ.

Did these 4 people feel any guilt in the assassination of President Lincoln?  Was it Stanton's guilt that made him work so hard to find John Wilkes Booth and his conspirators?  Was that what made Major Eckert throw himself into the investigation to find Booth; wasting many hours interrogating Lewis Payne, which wasn't his job?  General Grant, in his memoirs, lightly passed over the snub from him and Mrs. Grant leaving Washington on April 14th.  But I find more interesting, what would Mrs. Grant's attitude be?

Would President Lincoln have lived if only Major Eckert, Secretary of War Stanton or General Grant had accompanied him to the theater that fateful night?