I have tried to make the notes REGARDING THE 2ND FLOOR OUTDOOR LIGHT which I e-mailed you last night less ambiguous. I apologize for the redundancy and for the intrusiveness.

My respectful suggestions are: 

I) That on the attached image you note the confusingly inconsistent different locations of connecting screws on the two left most switches, (Ace Hardware $2.39 and Home Depot $2.52) I bought some of both, and wasted a lot of time before identifying the source of my confusion.

II) that you google "three way switch" and review the circuit diagrams, and that you ask me if you have questions.

II a) Note that the white wire, when used as a ground return is never attached to any switch.

II b) Note that the three-way-switch upstream at the proximal end of the installation is mechanically identical with the three-way-switch downstream at the distal end of the installation. 

II c) Note that the two conductors connecting the upstream and downstream switches are fastened to corresponding sets of two screws on each of the two switches.  The individual attachments at each set of two screws are not specific and may be alternated ad libitum.

II d) Note that on the upstream switch, the input conductor is always at 120V; Note that on the downstream switch, the output conductor is at 120V when the switches are set to turn the light on, and is at 0V when the switches are set to turn the light off. 

II e) Note that the lamp receives its 120V from a wire connected to the output of the remote downstream switch, but that the lamp may receive its white wire ground from an otherwise unrelated local circuit.

II f) Note that the screw on the downstream switch to which the lamp is attached, corresponds to the screw on the upstream switch to which power is supplied.

AMENDED NOTES REGARDING THE 2ND FLOOR OUTDOOR LIGHT:

a) In wiring, especially the "three-way" and "four-way" stair circuits, where one set of lights on two or more levels is controlled by one or more switches, I have sometimes found it practical to make the required white wire ground connections separately at different locations, relying on the fact that the white wire ground connection is in the center of the 240 Volt transformer, and that therefore the required white wire ground connection would be the same for voltages from either side of the transformer. (Ask me for details, if this seems obscure.) The three-way-switches themselves require only a bare-copper ground, but no white wire ground connection.

b) In stair circuits where the white wire ground connection could be supplied more conveniently separately at the distal end, I have (sometimes), instead of the three conductor - black, red, white and bare copper cable, used a two conductor #14 Romex cable - black, white and bare copper, to make the connection between two light switches on different floors. Then the 120V voltage would be switched back and forth between the black and the white wire whenever the switch was toggled. !! - Whenever I have used a white wire to carry voltage, I have wrapped it with a piece of black insulating tape as a marker. If you find such black tape on a white wire, you can assume that this wire carries a 120V voltage.

If there is a three conductor black, red, white, bare copper cable between the outside upstairs and downstairs light switches, it would have been reasonable for me to use two of the three conductors to connect the two toggle switches, and the third of the three conductors to connect the downstairs toggle switch to the upstairs outside light. It also seems likely - I can't remember, - that a downstairs outside receptacle if there is one, at the western end of the north wall, would have been wired directly through the wall separate from the other outside installations.

c) Testing the wiring of the three way switch: The three way switch has a ground screw which should be kept connected to a bare ground wire.  The three way switch has three connections for 120V wires. On the upstream switch (which I believe is upstairs where you are working) there is one input wire. Identify it by measuring the voltage on all connected wires. Use the metal switch box as a covenient ground. The input wire should always register 120V against ground, no matter to which position the switch is toggled.  Now measure the voltage between each of the remaining two screw terminals and ground. As you toggle the switch, the voltage to ground on each of the remaining screw terminals should likewise toggle between 120V and 0V.  If this is the case, you can proceed to step d) below.

If this is not the case, if on toggling, one of the screw terminals intermittently receives 120 V while the other remains at 0V, the two wires have been inadvertently reversed. To correct this fault, first, wearing protective glasses, detach from screw no. 2, wire no. 2, identified by the circumstance that it has 120V to ground no matter what position the toggle. As you remove wire no. 2, be careful not to touch wire no. 2 to yourself or to any metal ground, and cap wire no. 2 temporarily with a wire nut. Now detach from screw no. 1, wire no. 1 voltage on which you were able to toggle on and off. Attach wire no. 1 to screw no. 2. Then, being careful not to touch either yourself or any ground with the "hot" wire no.2, attach wire no.2 to screw no.1. 

d) If there is a wire attached to screw no. 3, note the color of the wire and leave it in place.  The light should be susceptible to being turned on and off from the upper switch and from the lower switch.  

If no wire is attached to screw no. 3, look for an unattached black, red or white wire. Measure the voltage to ground on this unconnected wire with the toggle switch in each of its two toggle positions. If you detect no voltage on the unconnected wire with the toggle switch in either position, attach the unconnected wire to screw no. 3. DO NOT attach to screw no.3 any unconnected wire that shows a voltage with any position of the toggle switch. The light should now be susceptible to being turned on and off from both above and below.  Both upper and lower receptacles should have power at all times.