Thank you to all replies so far. I have continued debugging and found the spesific line of code where everything grinds to a halt, still no clue why the content of my pins array is relevant since at that point in the process the pins in questions are not used.
However I wrongly assumed that the problem was with all Analog pins, the issue is spesifically if A4 and A5 (58 and 59) are used.
Looking into the datasheet of the ethernet board I am using it doesn't say it uses those, and they are not used elsewhere in the code. If anyone has any ideas why these two pins are special I'd appreciate the help, in the mean time I'll look into them and the libraries I use in case they are hardcoded somewhere or something.