Code P0449 No power going to EVAP canister?

Hello, are you setting your meter on DC voltage? It looks like you have the meter on the Amperage scale, if it's set with the dial facing down on the A (Amperage Scale). You need to be on the V voltage scale. You should have 12volts on the red/white wire all the time, key On or Off.
Unplug the Vent valve and check the red/white wire and see if you have 12volts then. On the DC Voltage setting. Not the V that looks to be AC voltage, the one above that, the V set on 60. That should be a 60v DC scale. and recheck for 12volts with the solenoid unplugged.
The reason the ECM is setting this code is probably because it's not seeing 12-volts on the white wire while the solenoid is not activated. When the ECM activates the solenoid the 12volts coming through the solenoid will be pulled to ground and the white wire will read 0 volts.
You would do better here using a test light, that way when you check the power feed coming in the test light will put a small electrical load on the circuit.

If you have 12volts while its unplugged, next set your meter on the Ohms (resistance) setting (3rd picture) and measure across the solenoid pins while it's not plugged in, if you don't get any reading at all then it's an open circuit inside the vent valve and it needs to be replaced.

https://www.2carpros.com/articles/how-to-use-a-test-light-circuit-tester

https://www.2carpros.com/articles/how-to-use-a-voltmeter

This is the Fuse that should power the Vent valve, it's in the fuse panel on the passenger side interior, behind the kick panel where the passenger's right foot would be. It's labelled CNSTR FUSE 10amp, it should have power at all times, see if there is power on both sides of the fuse. Then take it out and visually inspect it just to be sure. If it's okay and there's power on both sides and it's not blown, then we need to work down the circuit to find the location where the wire is probably broken. If you live in an area where they use salt on the roads during winter, the Evap components in the rear under side of the vehicle always end up with damaged and corroded wires. You can also follow the Red/White wire from the vent valve from the rear of the vehicle up towards the front, but they are usually damaged where the harness is exposed to the elements, it might be inside the black conduit that covers the wires, or rubbing against the frame, If it rubs against the frame it will short out and you'll find the fuse is blown., You can use an automotive light bulb on the red/white wire because it is a 10amp fuse, and most of automotive bulbs don't pull that many amps, just don't use a head lamp bulb, You can buy a test light from any auto parts store for pretty cheap, that way you can just use the clip on the test light to hook to any ground on the vehicle, the frame etc.

https://www.2carpros.com/articles/how-to-check-a-car-fuse

Did you have this worked on recently? Yes, the 10amp fuse is missing, that's highly suspicious. It didn't fall out.

Yes.

It's very strange that it's missing like that, I've never seen a fuse just fall out, unless the pins were spread. Even before you put the fuse in you should have power on one of the fuse location tabs. That circuit is hot at all times, so there should be 12-volts on both sides of the fuse as soon as you put it in. Make sure it's a tight fit too. If that's the actual problem, it's definitely a first. I think I can see pins in that open fuse location, when a fuse isn't designed to be in a certain location there are usually no electrical pins in that spot. Put any fuse in for now, if you still have the vent valve unplugged, you're just checking for power back there at this point.
But let me know what you find.

There are no codes stored in the engine computer but there might be codes stored in other modules. Basic OBD2 scan tools only scan the ECM and not the entire vehicle. You may have codes stored in the transmission control module. I would start by having a full system scan done, at 40 to 60 mph it sounds like you might be having an issue with the torque converter lock up solenoid, or possibly some shift solenoids problems, these won't always set codes in the ECM, so you need to use or have someone with a capable scan tool do a full system scan of the entire vehicle. I'm sure you will find codes in modules you are not even aware of. There are always codes stored in other modules. AutoZone will not have a scan tool capable of these scans, you need to use a higher end scan tool. If you're going to continue to repair your own vehicle it's worth investing in a decent scan tool that can provide much more information as well as run functional tests and bidirectional controls.