footprintsymbol [~]
Altium (and I'm sure other PCB Design software) supports both numeric and alpha for pin designator. This is not the pin display name, like you would see on a schematic. This is how the footprint will align with the schematic symbol.
I've used pin numbers to align symbols to footprints in the past, but I'm curious what the general practice is – pin numbers vs pin names ?
Are there any benefits (short term or long term) to choose one or the other ?
In CvPcb there is the "View selected footprint" in the top toolbar.
Once you press that button, a new window pops-up where you can see your footprint.
This new window allows you see the component and has a grid from which you can find out the size of your component. This grid is also selectable by right-clicking the grid and choosing whatever grid you want from "Grid Select" option.
If you mouse-hover on one pin, on the bottom of the window there are X-Y coordinates from which you can tell the distance between the pins. This one, from the example, has 5.08mm * 2 = 10.16mm = 0.4inches distance between the pins.
An off-page connector for an output should be drawn as an out arrow even if the output sinks current. Here's an example.
Block diagram perspective:
Detailed perspective (contents of the green block):
Best Answer
If in doubt, use the same designators that the datasheet for the part is using. Usually, datasheets use simple numbers for pins.
Some parts require alpha-numeric string for pin "number".
Both drawings from datasheet for MSP430F5500.