arios, it's not just you or your equipment, that kind of board is pretty difficult to work on, as it has cheap lead free solder and it's not very friendly to work with. As you now know, it's easy to lift pads and damage traces.
Also, getting that USB connector soldered back will take some doing. it's going to be much harder to solder to the usb pads than to the place where the wire normally goes. you will likely need a much smaller tip to do it at all and it's only a 1 layer pcb there, and the pads are really close.
as it is now, this is a much more difficult project than I would expect a newbie to accomplish. I'm up for a challenge, so if you are OK to ship it to the USA and back I will do the labor for free.
I'm actually not 100 % sure what's going on with that spacebar, it looks like it can go in place the way it is now or rotated 180 degrees. I annotated the image with what lines are connected where, but there are some that are on the other side of the pcb, so I don't know where they go to. Do you have a multimeter to test continuity with?
here's the image. the red lines used to be connected and the yellow also, those go to the spacebar LED. Again, I'm not 100% sure what's going on there because it looks like it's possible to install the spacebar upside down so I'm not sure how they have it wired logically.