I've asked several times for someone to prove that anyone else but the shooter (including their shooter) knew there was to be an attempt made on Kennedy that day.
None so far. Too soon I guess.
...which is equal to the number of times you've justified your position that Oswald probably did it.
On the other hand, there is some evidence of foreknowledge of the assassination via Rose Cherami, Joseph Milteer, Eugene Dinkin, Homer Echevarria, and Richard Case Nagell.