Also found the following problem. A crossed wire got unconnected and reconnected during the “align to grid” which was done to 25 mil and then again to 50 mil, and the system complains about two labels.
The short version is that ERC expects a pin of type “power output” on +12V net, but doesn’t find one, so it thinks the net is undriven. As a human engineer, you can see if that’s actually true, or if the net is in fact driven by something that KiCad doesn’t understand is a power source (for example, a connector to an external power supply). There is a dummy symbol PWR_FLAG in the power symbol library that can be added to the net to politely tell KiCad that the net is actually driven.
to answer your questions:
From what I’ve seen, blendtec blends most things
It might be or it might not be; is that net actually getting +12V from somewhere? It probably is, and KiCad just doesn’t understand where it’s coming from.
Yes, you can layout (but check that it’s not a real design issue!)
Add a PWR_FLAG to that net, assuming that it’s not a real design issue.
Hard to say here, but check that the wires and there connections match the original schematic, and check that all the labels are placed on the right wires.
I know this isn’t the world’s most useful reply, but just in general, I would never bother running ERC on an imported project (unless I was looking to fully port the whole project over to KiCad, in which case there’d be a phase of re-drawing a lot of it). ERC is very coupled to KiCad’s particular quirks/conventions.