Hello! Looks like a cool project. I am currently on the same step as my rebel rebuild. The last step in fact! For now...
Anyway I think the constant signal light means that your relay might need replacing. From a few videos and reading the service manual if you did a wrong ground hookup in the process of connecting everything back up you can blow a fuse. You can check by removing the relay and continue the circuit with a piece of wire. If you turn on the blinker and it's solid it means the relay needs to be replaced.
But I too need help with this!! I have very similar if not the same new rear blinkers.
I also have a similar looking tail/brake light combo with a license plate mount.
So the brake light has 3 wires; yellow/green, black and red. The blinkers have 3 a piece; black,brown, and red.
The cluster from the old setup has 4 green, 2 brown, 1 light blue, 1 orange, and 1 yellow/green.
So far I can get the rear brake light to light up as just rear light but it wont go bright when i apply the brake.
I have gotten the rear blinkers to light up in trying to connect them correctly in the beginning of the process. But there is a problem with that as well. I have taken it out for a quick ride around the block when i had gotten it all back together in the rebuild and did have rear lights and I would use the turn signal out of habit and the front blinkers worked for a while but then stopped working and now I can't get the blinkers to light up. Before i do any more potential damage i'm gonna check all the fuses and replace any blown ones. I would love any advice about how to differentiate wiring coloring schemes with aftermarket lights.