The main question:
Do I need to electrically connect SMD pad 1 to TH pad 1 (and same to pad 2)? As you can see they WILL be electrically connected as the pads intersected each other. But can I be sure that I will not need to put a hollow trace between them during tracing?
Auxiliary question 2: is that correct that first (square) pad is a cathode?
I don’t know who said it, but it came up some days/weeks ago in regards to pads with rounded corners, that the centers of the pads that are on the same net to not cause ratsnest leftovers need to overlap into the other pad or somesuch… (somebody made custom pads with rounded corners out of rectangular and circular pads).
If you can life with that, as long as the copper overlaps it should be fine electrically, just KiCAD might like it closer together.
Ah, found it:
Depends on the diode you got and what the manufacturer/distributor defines in the datasheet… so no rule of thumb as far as I know.
The only thing I’m 95% sure is, that the bonding wire is on the anode side (chip on kathode).