My honest advice is to not bother, it sounds like a bit of a problem child so best off saving and buying a better condition car.
However, brake light could just need a fault scanner to reset the warning message. The window would involve removing the door skin which isn't a hard just, but loads of bolts of different sizes so requires careful attention to detail. The boot not opening could be a fault mechanism/badge so could possibly need swapping (again, a fault code reading via VCDS for example would show this up). Swapping the rear badge for a whole new unit is more of a pain as the boot trim likes to snap it's clips when you remove it.
Most of those jobs are home mechanic level but as I said at the start, few quid more nets you a car with less problems.